1. Vincent Kompany - Hamburg to Manchester City - £6m
A 22-year-old Vincent Kompany was signed in the summer of 2008, costing £1m more than Tal Ben Haim and £4m less than Wayne Bridge.
Regarded as one of the world's best when fit, Kompany led the Citizens to four league titles and a further six domestic trophies during his time as City captain.
2. Robert Lewandowski - Lech Poznan to Borussia Dortmund - £4m
The Iceland volcanic ash cloud prevented Lewandowski from flying to Blackburn Rovers in 2010, and the Polish striker moved to Dortmund instead. Lucky escape, Rob mate.
Lewandowski scored a prolific 103 goals in 187 games in a yellow shirt, as he announced himself as one of the deadliest strikers in Europe and helped Dortmund to two consecutive Bundesliga titles.
3. Henrik Larsson - Feyenoord to Celtic - £650,000
A legal dispute with Feyenoord meant Larsson was allowed to leave for Scotland and what a move it proved to be.
The Swedish striker scored an astonishing 242 goals in 313 Celtic appearances, earning him the nickname 'The King of Kings' from the Celtic Park faithful.
4. Marcelo - Fluminense to Real Madrid - $8.7m
The teenager left his homeland in 2006 to move to the Bernabeu and has since gone on to become a club legend.
Regarded by many as the best left back in the world, Marcelo has won 20 trophies with Real Madrid and played an integral part in Los Blancos' back-to-back-to-back Champions League trophies.
5. Demba Ba - West Ham to Newcastle - Free
The now Premier League cult hero arrived in England in January 2011 but Ba's seven goals in 13 games couldn't prevent West Ham's relegation, which in turn allowed him to leave the club for free.
Alan Pardew's Newcastle swooped in and Ba went on to score an impressive 29 goals in 58 games at St James' Park, as he formed a prolific partnership with Papiss Cisse and fired the Magpies to a fifth place in his debut season.
6. James Milner - Manchester City to Liverpool - Free
James Milner on a free transfer just makes sense. No frills. Job done.
The Englishman has been a key player for Jurgen Klopp in midfield and at full back, helping the Reds win their sixth Champions League trophy last season.
7. Michu - Rayo Vallecano to Swansea - £2m
Remember him? What a bloke. Michu ran riot in his debut season on the Welsh seaside in 2012, scoring 22 goals in 43 games as Swansea went on to lift the League Cup. The Spanish striker was named the club's Player of the Year by his Swans teammates and supporters, but his career would, unfortunately, never reach those heights again.
Still, a Michu became a unit of measurement for transfer fees for years to come. The absolute pinnacle of bargain transfers.
8. Cesar Azpilicueta - Marseille to Chelsea - £6.5m
An unknown right back upon arrival in 2012, Azpilicueta has missed just two Premier League games since 2015 and established himself as one of the strongest defenders in the country over the last few seasons.
9. Paolo Di Canio - Sheffield Wednesday to West Ham - £1.75m
When Di Canio made the move to West Ham, he was in the middle of an 11-match ban for shoving a referee to the ground after being sent off, which may have knocked a few pennies off the price.
Still regarded as a club legend, the controversial forward scored 50 goals in 128 games for the Hammers, including THAT volley against Wimbledon which was later voted the Premier League's goal of the decade.
10. Michael Ballack - Bayern Munich to Chelsea - Free
During his time at Bayern Munich, Ballack had established himself as one of the most formidable central midfielders in Europe but the Blues managed to pick up on a Bosman in 2006.
The German Rolls-Royce was influential on and off the pitch, as he helped Chelsea to two FA Cups, one League Cup and one Premier League title in his four-year spell.
11. Esteban Cambiasso - Real Madrid to Inter - Free
After failing to establish himself at the Bernabeu, Cambiasso's contract with Madrid was allowed to expire and he made the move to Italy on a free transfer in 2004.
The Argentine midfielder remained at San Siro for a whole decade, making 431 appearances for I Nerazzurri and winning 15 trophies.
12. Robin van Persie - Feyenoord to Arsenal - £2.75m
Feyenoord wanted £5m for their young striker - even that would have made this list.
Following his 2004 move to Arsenal, Van Persie grew to be one of the best strikers the Premier League has ever seen, scoring 132 goals in 280 games...
13. Ashley Cole - Arsenal to Chelsea - £5m + William Gallas
After a successful career at Arsenal, Cole made the switch to bitter rivals Chelsea on deadline day in 2006 for just £5m with William Gallas moving the other way.
There's no doubt which club got the better end of the deal, as Cole went on to win eight trophies in his 338 appearances and was widely regarded as the best left back in world football during his time in a blue shirt.
14. Andy Robertson - Hull City to Liverpool - £8m
One of the biggest bargains of recent years. Relegated with Hull in 2017,
15. Jay-Jay Okocha - PSG to Bolton - Free
Okocha became the most expensive African player of all time when he was signed by Paris Saint-Germain for around £14m, but four years later he arrived in England on a free transfer.
One of the most gifted players the Premier League has ever seen, the Nigerian midfielder made 141 appearances for Bolton and led them to their first cup final in nine years.
16. Cristiano Ronaldo - Sporting CP to Manchester United - £12m
He was relatively cheap. He went on to become *Cristiano Ronaldo*. It's a bargain, alright?
17. David Ginola - PSG to Newcastle - £2.5m
His time at Newcastle was too short for Magpies fans, leaving after just two years, but Ginola played a part in a memorable time in the club's history as they challenged for the league title during both of his seasons with the Magpies.
18. N'Golo Kante - Caen to Leicester City - £5.6m
In 2015, an adorable little Frenchman arrived in Leicester. The world didn't know what was coming. Not even Kante himself could have predicted what he would go on to achieve in the following four years.
His one and only season with the Foxes saw him play an instrumental role in Leicester's stunning title win in 2015/16, missing just one game and earning a place in the PFA Team of the Year. Even his £32m move to Chelsea the following summer is also probably eligible for this list.
19. Edwin van der Sar - Fulham to Manchester United - £2m
After four years with Fulham, the 6'5 goalkeeper was signed by Sir Alex Ferguson and would go on to become one of United greatest ever goalkeepers.
Van der Sar played a huge role in the seven trophies won by United during his Old Trafford days, particularly in the 2008 Champions League final where he was the shootout hero against Chelsea.
20. Patrick Vieira - Milan to Arsenal - £3.5m
21. Seamus Coleman - Sligo Rovers to Everton - £60,000
In footballing terms, that is peanuts. You could get 33 Seamus Colemans for the price of a single Michu.
Coleman was signed by David Moyes in 2009 and he would prove to be one of the league's top full backs over the next few seasons.
22. Eric Cantona - Leeds United to Manchester United - £1.2m
With 77 goals in his 171 appearances, Cantona was certainly value for money. One Crystal Palace fan might disagree...
23. Andrea Pirlo - Milan to Juventus - Free
Pirlo and Milan mutually decided against a new contract in 2011 and the midfielder made the switch to rivals Juventus for nothing, in what Gianluigi Buffon described as the "signing of the century".
Like a fine wine, Pirlo got better with age and enjoyed a phenomenal spell in Turin. He lifted four league championships and three domestic trophies, while winning three consecutive Serie A Footballer of the Year awards.
24. Robert Lewandowski - Borussia Dortmund to Bayern Munich - Free
The 30-year-old has scored a staggering 191 goals in 242 games, with his feat of scoring five goals in eight minutes and 59 seconds after coming off the bench against Wolfsburg in 2015 earning Lewandowski four Guinness World Record certificates. Should have gone to Blackburn, though.
25. Raul - Atletico Madrid to Real Madrid - Free 26. Riyad Mahrez - Le Havre to Leicester City - £400,000 27. Alessandro Del Piero - Padova to Juventus - £421,000 28. Dani Alves - Juventus to PSG - Free 29. Jordi Alba - Valencia to Barcelona - £11.2 m
30. Gary Cahill - Bolton to Chelsea - £7m
Gary Cahill left a Bolton side doomed for relegation in January 2012 and within five months he was lifting the Champions League trophy after beating Bayern Munich in their own backyard, kickstarting what would be a trophy-laden Chelsea career.
Cahill lifted eight trophies in seven years in west London, playing an integral part in almost every one and earning club legend status with the Blues fans.
31. Peter Schmeichel - Brondby to Manchester United - £500,000
The Danish goalkeeper was signed as a relative unknown in 1991, but he caught the eye of United with his performances for Brondby in the UEFA Cup.
Regarded as one of the greatest of all time, Schmeichel kept 156 clean sheets in 348 appearances for United, with Sir Alex Ferguson later describing the deal as "the bargain of the century".
32. Philippe Coutinho - Inter to Liverpool - £8.5m
In and out the side at Inter, Coutinho's career truly began at Anfield, where he earned the nickname 'The Magician'. He was named both Liverpool's Player of the Year and Players' Player of the Year in successive campaigns.
33. Frank Lampard - West Ham to Chelsea - £11m
Harry Redknapp wasn't joking when he said the then-West Ham youngster would go right to the very top.
Probably Chelsea's greatest ever transfer at just £11m, Lampard went on to become the club's highest ever goalscorer with 211 goals from midfield, winning 11 trophies including captaining Chelsea to their 2012 Champions League triumph.
34. Paul Pogba - Manchester United to Juventus - Free
Juventus, kings of the free transfer. Limited opportunities at United forced Pogba to leave at the end of his contract in 2012, when he chose to join the Italian giants.
He helped Juve to four consecutive Serie A titles while he established himself as one of the world's best young talents, picking up the Golden Boy award in 2013.
35. Jadon Sancho - Manchester City to Borussia Dortmund - £8m
With a plethora of attacking options in his way, Sancho made the bold call in 2017 to leave Manchester City and forge a career in the Bundesliga.
The 19-year-old had a stellar 2018/19 season, scoring 12 and assisting 17, while also breaking into the England team. At £8m, Dortmund have played a blinder.
36. Aaron Ramsey - Arsenal to Juventus - Free
JUVENTUS IN FREE TRANSFER SHOCKER. Ramsey is their latest Bosman signing after the Welshman failed to agree a new deal at Arsenal.
Arsenal will desperately miss Ramsey in their midfield and Unai Emery has a job on his hands to replace him. A great move for the midfielder and another smart piece of business by Juve.
37. Miroslav Klose - Bayern Munich to Lazio - Free
Even at 33, the opportunity to sign Miroslav Klose on a free is not to be sniffed at. Germany's all-time leading goalscorer took his talents to Italy and proved class is permanent, scoring 63 goals across five seasons.
38. Sol Campbell - Tottenham to Arsenal - Free
Campbell paid more of a price with this transfer than Arsenal did. His reputation with Spurs fans was in tatters, but after winning two Premier League titles and two FA Cups with the Gunners, the defender can sleep easy.
39. Ruud Gullit - Sampdoria to Chelsea - Free
The most expensive player in the world at one time, Gullit moved to Chelsea at the end of his career in 1995. This transfer and the period that followed is regarded by some as the catalyst for the Blues' transformation into an elite club.
40. Jurgen Klinsmann - Monaco to Tottenham - £2m
Klinsmann's arrival was met with hostility due to his role in England's exit from the 1990 World Cup, but the critics were soon won over by his personality on the pitch and he now holds legendary status at Tottenham, returning to the club on loan for the 1997/98 campaign and helping them avoid relegation (yep, really).
41. Dele Alli - MK Dons to Tottenham - £5m
Alli was signed as an 18-year-old in 2015 by Mauricio Pochettino and his potential became evident in no time at all - h
42. Roberto Baggio - Milan to Bologna - Free
Baggio may have downgraded from Milan, but his time at Bologna was a huge success. The Italian scored a personal best of 22 goals in Serie A in his first season, which earned him a Ballon d'Or nomination.
But he did cut off his ponytail to 'signify his rebirth', so thanks a lot, Bologna.
43. Zlatan Ibrahimovic - PSG to Manchester United - Free
Jose Mourinho brought the infamous striker to Old Trafford at the start of 2016/17 and even at the grand old age of 35, it proved to be a masterstroke.
Ibrahimovic bagged 28 goals in 46 appearances during his first season, as United finished the season with a League Cup and Europa League trophy. Oh, and the Community Shield, sorry Jose.
44. Petr Cech - Rennes to Chelsea - £7m
There once was a time you could buy a world class goalkeeper for less than £60m. Crazy.
Cech made an instant impact at the Bridge, keeping a record 21 clean sheets in the Premier League in his debut season, before progressing to become Chelsea's greatest ever keeper.
45. Ole Gunnar Solskjaer - Molde to Manchester United - £1.5m
The Baby-Faced Assassin earned legend status for his role in United's 1999 treble win.
46. Branislav Ivanovic - Lokomotiv Moscow to Chelsea - £9.7m
No one had heard of Ivanovic before his move to Chelsea in 2008. Well, no one had heard of Ivanovic eight months into his Chelsea career either.
But fast forward nine years and Ivanovic left the Blues as a club legend, playing an integral part in a trophy-laden era.
47. Esteban Cambiasso - Inter to Leicester City - Free
Yeah, that happened.
Cambiasso rolled back the years during one season with the Foxes, where he was named the club's Player of the Year for 2014/15.
48. Luka Jovic - Benfica to Eintracht Frankfurt - €7m
After an exceptional loan spell, Frankfurt exercised their option to buy Jovic in April, knowing they would sell him for big bucks over the summer - £52m of them, to be exact.
Business is business.
49. Callum Wilson - Coventry City to Bournemouth - £3m
Wilson had been at Coventry for five years, with a couple of loans to non-league sides along the way. Now a full England international, Wilson is one of the best strikers outside the top six of the Premier League.
50. Sami Khedira - Real Madrid to Juventus - Free
Death, taxes and a free transfer to Juventus. Upon the expiry of his Madrid contract, Khedira made the move to Serie A and has enjoyed a successful career in Italy so far.
Khedira has played a big part in Juve's four consecutive title wins, with 127 appearances to his name so far.