30) Benjamin Mendy - Monaco to Manchester City (£52m, 2017)
No team will appear on this list as a selling club more than Monaco, which may explain why they've gone from French champions to relegation strugglers in less than two years.
Two of their title-winning team from 2016/17 joined Manchester City, with Benjamin Mendy following Bernardo Silva to the Etihad Stadium. In his first season in England he became a Premier League champion, despite spending most of the campaign recovering from a cruciate ligament injury.
After a promising start to this season, Mendy once again found himself injured, missing over two months. He recently returned to fitness - a huge boost to Manchester City's title hopes.
29) Oscar - Chelsea to Shanghai SIPG (£52m, 2017)
Chinese transfer fees are notoriously difficult to pin down, with estimates for Carlos Tevez's move to Shanghai Shenhua in 2017 ranging between £12m and £72m depending on who you believe and how you calculate it.
The only Chinese transfer we can confirm in the top 30 is Oscar's move to Shanghai SIPG in 2017. The Brazilian had slipped down the pecking order at Stamford Bridge and decided to take a big payday in the Far East, linking up with former Brazil teammate Hulk.
Unlike Tevez, Oscar didn't let his standards drop and has taken advantage of the lower quality league to rack up some impressive statistics, with 25 goals and 41 assists in just two years.
28) Naby Keita - RB Leipzig to Liverpool (£52.75m, 2018)
Liverpool identified RB Leipzig's tough-tackling, dynamic midfielder Naby Keita as the player who could transform them into title contenders, and were even prepared to wait a year for his arrival after reaching an agreement in 2017.
The Reds have indeed become title challengers since Keita's arrival, though the Guinean can claim little credit. He has started less than half of Liverpool's Premier League matches and is yet to score his first goal in English football.
European football may prove to be more his speed, and facing familiar German opposition Bayern Munich in the last 16 of the Champions League could bring the best out of him.
27) Kevin De Bruyne - Wolfsburg to Manchester City (£55m, 2015)
Two years after Jose Mourinho decided that Kevin De Bruyne wasn't good enough for the Premier League, Manuel Pellegrini brought him back to England, paying a hefty sum to sign the Belgian from Wolfsburg.
De Bruyne has been worth every penny spent, with his performances in the 2017/18 season affirming his status as one of the best players in the Premier League. He won the inaugural Playmaker Award for most assists and narrowly missed out on the PFA Player of the Year award to Mohamed Salah.
Injuries have restricted De Bruyne to just a few starts this season, but if he can maintain his fitness then City have a good chance of winning every trophy available to them.
26) Edinson Cavani - Napoli to Paris Saint-Germain (£55m, 2013)
Arriving at Paris Saint-Germain after they had just won their first league title in two decades, Edinson Cavani helped to establish Les Parisiens as the dominant force in French football. They have won 17 of the 20 domestic competitions they have entered in Cavani's five years on board.
Throughout his PSG career, Cavani has never been the club's poster boy, overshadowed first by Zlatan Ibrahimovic and then by Neymar and Kylian Mbappe. However, his consistency has never been in doubt as he has always scored at least 25 goals each season.
In recent years he has been particularly lethal, scoring 63 league goals in his last two seasons to win the Ligue 1 golden boot on both occasions, outscoring both Neymar and Mbappe last season.
25) Kaka - AC Milan to Real Madrid (£56m, 2009)
One of the best midfielders of his generation and a Ballon d'Or winner in 2007, a world record move to Real Madrid seemed like the natural step for Kaka when AC Milan's status in European football began to slip in the late 2000s.
But like the Rossoneri, Kaka's best years were behind him. Injuries disrupted his first two seasons at the Bernabeu, with Mesut Ozil taking his place in the side, and he also had a troubled relationship with Jose Mourinho.
The huge loss Real Madrid made when they sold Kaka back to Milan in 2013 means that this is regarded as one of the worst transfers of all time.
24) Zlatan Ibrahimovic - Inter to Barcelona (£56m, 2009)
A world class player, moving from Italy to Spain, for £56m, in 2009. Spanish football fans were having
Ibrahimovic's only season at the Nou Camp wasn't that bad, as he scored 16 La Liga goals, but fans were scratching their heads as to why Samuel Eto'o - an equally brilliant striker - had been allowed to join Inter in part exchange.
Ibrahimovic resented having to share the limelight with Lionel Messi and accused Pep Guardiola of being a coward after a Champions League defeat.
23) Alisson Becker - Roma to Liverpool (£56m, 2018)
Loris Karius' disastrous performance in the 2018 Champions League final forced Jurgen Klopp to swallow his pride and dip into the transfer market for a world class goalkeeper. He plumped for Alisson Becker, Roma's Brazilian shot-stopper who had earned rave reviews in Italy.
Alisson's impact is reflected in Liverpool's defensive record, which has seen them concede fewer goals than any other team in the Premier League this season. He has come to the fore with some memorable saves against Brighton, Chelsea, Burnley, and most notably Napoli.
With Liverpool's defence suffering a number of injury casualties, Alisson will be needed all the more in the remainder of the season if the Reds are to end their wait for that elusive league title.
22) Pierre-Emerick Aubameyang - Borussia Dortmund to Arsenal (£56.1m, 2018)
After years of treading water, this is the sort of signing Arsenal need to make more of if they want to become a force to be reckoned with again. Mislintat's imminent departure from the Emirates Stadium is a real blow in that regard.
21) Aymeric Laporte - Athletic Bilbao to Manchester City (£57m, 2018)
Athletic Bilbao's unique transfer policy allows them to command much higher fees for players than other clubs would be able to, but Manchester City fans will agree that Laporte was worth every penny paid if he helps them to retain their Premier League crown.
Laporte joined City in January 2018 when they were already 12 points clear of their nearest rivals and played on and off until the end of the season. In 2018/19 he has become City's main defender, starting almost every match this season for the title challengers.
Arguably his most important City performance came in the recent match against Liverpool, when he deputised superbly at left back in a crucial victory for Pep Guardiola's side.
20) Christian Pulisic - Borussia Dortmund to Chelsea (£58m, 2019)
The first 2019 transfer on this list saw Chelsea pay £58m to sign Christian Pulisic from Borussia Dortmund, the highest transfer fee ever paid for a North American player by quite some distance.
At just 20 years of age, Pulisic is already vastly experienced with over 100 Dortmund appearances under his belt. However, he was allowed to leave the German side after slipping behind Jadon Sancho in the pecking order, although he will stay until the end of the season.
It is expected that Chelsea will lose Eden Hazard to Real Madrid next summer, so they are hoping that Pulisic can fill the void left behind. It will certainly be a lucrative transfer in a commercial sense, with Pulisic being the poster boy of football in the USA.
19) Alvaro Morata - Real Madrid to Chelsea (£58m, 2017)
Antonio Conte's Chelsea downfall began when he decided to replace Diego Costa with Alvaro Morata in the summer of 2017. Costa had just scored 20 goals to help Chelsea win the Premier League title in 2016/17; Morata had never scored more than 15 in a league campaign.
Sure enough, Morata failed to have the expected impact. After a bright start, scoring six goals in his first six Premier League matches, he faded badly, hitting the target just five more times all season as Chelsea finished outside the top four and Conte was sacked.
Even the appointment of Maurizio Sarri couldn't get the best out of Morata, who is now at Atletico Madrid on loan. If Los Rojiblancos want to make the move permanent at the end of the season, they will be able to do so for a £15m loss on Chelsea's original investment.
18) Angel Di Maria - Real Madrid to Manchester United (£59.7m, 2014)
Angel Di Maria had been named man of the match in the Champions League final as Real Madrid finally clinched La Decima in 2014, so it looked like a good piece of business when Manchester United broke their transfer record to sign the Argentine a few months later.
He made a promising start at Old Trafford, winning Manchester United's player of the month award for September after two goals and two assists in four Premier League matches, including a sensational chipped finish against Leicester.
However, Di Maria's form soon took a nosedive and a costly red card against Arsenal in the FA Cup proved to be his final start for United as he was sold at the end of the season to Paris Saint-Germain for a loss of around £15m.
17) Riyad Mahrez - Leicester City to Manchester City (£60m, 2018)
How do you improve a squad which has just scored a record number of goals, won a record number of games and become the first side to surpass 100 points in the Premier League? Pep Guardiola's answer was to buy Riyad Mahrez from Leicester last summer.
City had been after Mahrez for at least a year, but their approach had been rebuffed the previous summer and Leicester held firm the following January despite Mahrez temporarily going on strike. The champions eventually got their man for £60m.
With just five goals to his name so far, Mahrez is yet to hit the heights which saw him named PFA Player of the Year during Leicester's unlikely title triumph of 2015/16, and his penalty miss at Anfield in October will be replayed over and over again if City don't win the title.
16) Frenkie de Jong - Ajax to Barcelona (£62m, 2019)
After months of speculation, the Frenkie de Jong transfer saga finally came to an end this month as the Dutch midfielder agreed to join Barcelona at the end of the season.
De Jong has been compared to both Johan Cruyff and Franz Beckenbauer, which is not as ridiculous as it seems, given that he possesses a Cruyff-like ability to float past players despite being closer to Beckenbauer in terms of his position and tactical flexibility.
Producing consistent performances in the Eredivisie is one thing; doing it in La Liga is quite another. If De Jong can learn from Sergio Busquets and become the Spaniard's successor, Barcelona will have a world class talent on their hands.
15) Thomas Lemar - Monaco to Atletico Madrid (£63m, 2018)
It's early days in the La Liga career of Thomas Lemar, but it's already starting to look like Atletico Madrid may have paid well over the odds for the Frenchman when they signed him from Monaco last summer.
In 18 league appearances, Lemar has just one goal and one assist so far for Diego Simeone's team, and Atletico fans are starting to fear that this might be Jackson Martinez all over again.
Simeone has pleaded patience, emphasising Lemar's talent and insisting he will come good. He will need to do so quickly if Atletico are to stand any chance of usurping Barcelona in La Liga or beating Juventus in the Champions League.
14) James Rodriguez - Monaco to Real Madrid (£63m, 2014)
Coming off the back of his performances at the 2014 World Cup, when he scored six goals and led Colombia to the quarter finals, James Rodriguez said it was his 'life's dream' to play for Real Madrid. Los Blancos were happy to oblige, splashing out £63m on the Monaco star.
Rodriguez was certainly living the dream in his first season at the Bernabeu, with 17 goals and 18 assists making him Real's third most creative player, behind only Karim Benzema and Cristiano Ronaldo. Alas, injuries meant that he couldn't maintain his promising start.
Seeking to rejuvenate his career, Rodriguez joined Bayern Munich on loan in summer 2017 and excelled in his first year, but injuries have once again slowed his progress. B
13) Kepa Arrizabalaga - Athletic Bilbao to Chelsea (£71.6m, 2018)
Alisson was the world's most expensive goalkeeper for less than three weeks last summer before he was replaced at the top of the list by Kepa Arrizabalaga, with Chelsea paying Athletic Bilbao top dollar to replace Thibaut Courtois.
The commanding Basque shot-stopper has settled in well at Stamford Bridge, with his height and agility ensuring that Courtois has not been missed. He cemented his popularity with the Chelsea fans by saving a penalty in the shoot-out which booked their place in the EFL Cup final.
With Petr Cech and Courtois, Chelsea's success in the modern era has always been built on the foundation of a solid goalkeeper, so Kepa's strong start to live at Stamford Bridge bodes well.
12) Virgil van Dijk - Southampton to Liverpool (£75m, 2018)
Some people were sceptical when Liverpool smashed their transfer record to make Virgil van Dijk the world's most expensive defender in January 2018, but 12 months later he is the most important piece of the jigsaw in the Reds' title bid.
With the Dutchman at the back, Liverpool reached the 2018 Champions League final, and their previously fragile defence is now the sturdiest in the Premier League, conceding just 13 goals after 23 matches this season.
Rated by many as one of the world's best centre backs, Van Dijk has shown that a good defender is worth his weight in gold. The likes of Kalidou Koulibaly, Milan Skriniar and Matthijs de Ligt could soon be changing hands for similar fees.
11) Luis Suarez - Liverpool to Barcelona (£75m, 2014)
No price tag would have been enough for Liverpool to happily part with Luis Suarez, but they couldn't stand in the way of his dream move to Barcelona, and he became damaged goods (even more so than before) after biting Giorgio Chiellini at the 2014 World Cup.
Liverpool's title challenge in 2013/14 season had been so dependant on the brilliance of Suarez that they crumbled without him, finishing 6th the following year and 8th the season after that. Not until signing Mohamed Salah did they fill the void Suarez had left behind.
At Barcelona, Suarez has proved why he is regarded as one of the best strikers in the world. He has scored 125 goals in 150 La Liga appearances and is the only player apart from Lionel Messi and Cristiano Ronaldo to win the Pichichi Trophy in the last nine years.
10) Romelu Lukaku - Everton to Manchester United (£75m, 2017)
Romelu Lukaku can count himself unfortunate to have come in for so much criticism since joining Manchester United in 2017. He averaged nearly a goal every other game in his debut season but was accused of not being mobile enough and only scoring against lesser sides.
With 27 goals in all competitions, last season was actually the most prolific of Lukaku's career. He has just nine goals to his name so far this season, but given United's lack of attacking inspiration under Jose Mourinho, Lukaku can't be completely blamed for that.
Since Ole Gunnar Solskjaer was appointed, Lukaku has already contributed to five goals, including two assists in the FA Cup win over Arsenal, so United fans may not have seen the best of him yet.
9) Gonzalo Higuain - Napoli to Juventus (£75.3m, 2016)
In their efforts to finally win that elusive Champions League, Juventus raided Serie A rivals Napoli for Gonzalo Higuain in 2016. It was a fair price for a striker whose 36 goals the previous season was the highest total in Serie A since 1928/29.
Higuain didn't quite scale those heights in Turin, though he did score 40 goals in 73 league appearances. As for the Champions League, Higuain scored five goals to help Juventus reach the final in 2016/17, but they came up short again, losing to Real Madrid in Cardiff.
After just two seasons at Juventus, Higuain was loaned out to Milan as part of the deal which brought Leonardo Bonucci back. Just six months later he's on the move again, joining Chelsea on loan to try and solve their striker crisis.
8) Cristiano Ronaldo - Manchester United to Real Madrid (£80m, 2009)
Nothing which costs £80m can be described as a bargain, but this will go down as one of the greatest transfers ever despite the extortionate price. Cristiano Ronaldo arrived at Real Madrid as one of the best players in the world and left having established himself as one of the best players of all time.
In nine seasons at the Bernabeu, Ronaldo scored a staggering 450 goals in 438 appearances, won the Ballon d'Or four times, and won every possible trophy at least twice, including four Champions Leagues.
The rivalry between Ronaldo and Lionel Messi means that this era of La Liga will always be remembered as one of the greatest periods in football history.
7) Gareth Bale - Tottenham to Real Madrid (£85.3m, 2013)
With his price tag naturally drawing comparisons to Ronaldo, Bale was under immediate pressure to succeed, but injuries marred his first six months. However, a sensational winner against Barcelona in the Copa del Rey final was the perfect way to ingratiate himself to his new fans.
Though Bale has struggled to maintain consistent popularity during his time in Spain, he has always had the ability to pop up with important goals in big matches, including the 2014 and 2018 Champions League finals.
6) Cristiano Ronaldo - Real Madrid to Juventus (£88m, 2018)
Guess who's back? The only man to appear on this list twice is inevitably Cristiano Ronaldo. Juventus watched Real Madrid win three consecutive Champions League titles and decided they wouldn't mind a piece of the action, and they were prepared to spend big to get it.
Of all the players on this list, Ronaldo was the oldest at the time of his transfer, but the 33-year-old appears ageless as he has taken to Serie A like a duck to water, with 15 goals already.
His European exploits have been less impressive, with only one goal in the Champions League so far, but we're into the knockout stages now, and nobody has ever scored more knockout stage goals in the Champions League than Ronaldo.
5) Paul Pogba - Juventus to Manchester United (£89.6m, 2016)
Sir Alex Ferguson didn't make many mistakes in his illustrious career, but allowing Paul Pogba to leave Manchester United for nothing in 2012 may be one of his biggest. Pogba's attitude was called into question, but that did not seem to be a problem at Juventus
Four years after letting him leave, Manchester United brought Pogba back to Old Trafford. He made a bright start before Ferguson's old reservations about his attitude began to resurface, and his performances deteriorated in correlation with his relationship with Jose Mourinho.
Pogba's ability has never been in question though, and he has been in sensational form since Ole Gunnar Solskjaer took over. Under the right manager, he might yet justify that fee.
4) Ousmane Dembele - Borussia Dortmund to Barcelona (£96.8m, 2017)
Barcelona took a leap of faith when they spent over
He isn't quite in that category yet, but after an injury-ravaged first season at the Nou Camp, Dembele is slowly proving that the faith in him was justified. He has 13 goals in all competitions this season and has nailed down a starting spot alongside Luis Suarez and Lionel Messi.
Statistics alone cannot convey how impressive Dembele has been, with some of his goals being truly mesmerising: a sensational strike against Sevilla, a sublime run and finish against PSV Eindhoven, and an exhibition of speed and strength against Tottenham.
3) Philippe Coutinho - Liverpool to Barcelona (£105m, 2018)
Philippe Coutinho joined Barcelona from Liverpool last January in search of trophies and acclaim, and he got what he desired - two trophies by the end of the season, and plenty of praise for his promising performances.
How quickly things have changed. As Dembele has prospered, Coutinho has struggled, and comparisons between the two do not make good reading for the Brazilian, who has just four goals and two assists in La Liga this season.
Neither missed by his old club, who are flourishing without him, nor beloved by his new club, where his place in the starting lineup is in danger - Coutinho's dream move is threatening to become a nightmare.
2) Kylian Mbappe - Monaco to Paris Saint-Germain (£150m, 2018)
Most of us weren't alive the last time a teenager did what Kylian Mbappe did at last summer's World Cup. Not since Pele in 1958 had a teenager scored twice in a World Cup match or scored in a World Cup final. He also became the youngest Frenchman ever to score at a World Cup.
For many people, Mbappe's performances in Russia confirmed that he is the player who will succeed Lionel Messi and Cristiano Ronaldo as the best in the world. No wonder PSG made him the world's most expensive teenager in 2017, with the transfer made official a year later.
However, Mbappe may struggle to fulfil his full potential at PSG, who dominate domestically but are yet to go beyond the quarter finals of the Champions League. If they can't get it right in the next few years, Mbappe may have to look elsewhere.
1) Neymar - Barcelona to Paris Saint-Germain (£198m, 2017)
Neymar's move from Barcelona to PSG in 2017 didn't so much break the world transfer record as smash it into a million pieces. He became the first player to command a nine-figure sum, with the £198m fee being more than double the previous record of Paul Pogba.
Was it worth it? Well, Neymar has scored 32 goals in 33 Ligue 1 appearances, PSG won the domestic treble last season, and his collaboration with Edinson Cavani and Kylian Mbappe is one of the best in Europe.
But for the price they paid, PSG need to see some significant progress in the Champions League. Neymar was injured as they were beaten by eventual winners Real Madrid in the last 16 last season, and he will miss the first round of the knockout stage against Manchester United this year too.