The transfer market is often full of mega-money deals, but here are the best who cost absolutely nothing. (You can thank little-known Belgian player Jean-Marc Bosman for allowing players to move for free after 1995.)

10) Esteban Cambiasso to Inter/Leicester

One of a couple of players on this list who have excelled as free transfers twice, Cambiasso was underused and then overlooked as Real Madrid sought glossier names in the early 2000s. Inter picked him up for nothing in 2004 and he became the fulcrum of a team that won five Scudetti and the treble in 2010. Then, when he departed after a decade in Milan, he helped save Leicester City from relegation in the season before they won the league. People often talk about manager Nigel Pearson deserving plenty of credit for that miracle, but you can include Cambiasso with that as well.

9) James Milner to Liverpool

Milner has been a contradiction for the past decade: you wouldn't put him in the first-choice XI of any team he played in at Manchester City or Liverpool, but at the same time he's been one of the most important and widely respected figures at both clubs. Perhaps the ultimate player whose versatility has been to the detriment of his reputation, since moving to Liverpool on a free in 2015, Milner has excelled on the wing, as a deep midfielder, as a driving No. 8 and in both full-back positions. He hasn't always been first choice, but he'll shortly add a third Premier League title to his collection and has won the Champions League. He'll probably take that.

8) Henrik Larsson to Barcelona

Larsson always seemed content that he didn't have to prove himself away from Celtic but, after scoring 242 goals in 313 games at Parkhead, and with his contract expiring in 2004, he decided he needed a new challenge. He was only at Barcelona for two seasons -- the first was significantly curtailed by a cruciate ligament injury -- but was respected by everyone. With Barca trailing 1-0, he came on in the 2006 Champions League final against Arsenal and turned the game around with two assists to land his first European trophy, and finished his spell at the club with 19 goals in 52 games.

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7) Ruud Gullit to Chelsea

As the 1987 Ballon d'Or and world record transfer holder, when he moved from PSV to Milan for 18 million guilders (around £6m) that same year, one could argue that Gullit's move to Chelsea on a free transfer in 1995 wasn't all that fruitful. In his one year as a player at Stamford Bridge he won nothing and Chelsea finished 11th, although they did come sixth and fourth and won the FA Cup after he became a player-manager in 1996. But his impact was mostly symbolic, a sign that the Premier League now meant business and could attract the best talent from around the world. His arrival influenced a whole generation that came after him.

6) Steve McManaman to Real Madrid

McManaman was perceived quite differently in England and Spain. At home, he was thought of as a wispy, skilful but slightly insubstantial winger, having spent nine years at Liverpool. After moving to Real Madrid on a free transfer in 1998, he was considered a grafter, someone who would do the running for the more creative players around him. But that made him loved at Real, and at the time of his departure in 2003, he was the most successful Englishman (by trophies) to ever play abroad as he had two La Liga titles, two Champions League wins and a Spanish and UEFA Super Cup.

5) Roberto Baggio to Bologna/Brescia

The natural logic of football is that the best players will want to play at the top clubs and will play their best there. But that never seemed the case with Baggio, who had spells at Juventus, Milan and Inter and never really seemed comfortable at any of them, though he did well, at Juve particularly. At Bologna and Brescia though, where he joined from Milan and Inter on free transfers respectively, he excelled more consistently, enjoying his most prolific season for league goals (22) in his single season with Bologna in 1997-98, and living out a golden autumn of his career with Brescia, playing brilliantly for four years and scoring 46 goals in 101 games in all competitions before his retirement.

4) Luis Enrique to Barcelona

Players don't often move directly between Spanish rivals Real Madrid and Barcelona, but out of two major ones who did, you could argue that Luis Enrique was more of a success at Barcelona than Luis Figo was at Real Madrid. He cost less, for a start: about €62m less, in fact. Luis Enrique, who moved to Camp Nou for nothing in 1996, won the league twice in what was a pretty moderate Barca side by the standards of what came before and after. And he then went on to manage the club, winning the treble in 2015.

3) Sol Campbell to Arsenal

At the time it was a scandal. A player who had come through the ranks to captain Tottenham, who had spent 12 years at the club, left for bitter rivals Arsenal on the expiry of his contract despite saying numerous times that he would be staying. The circumstances of Campbell's arrival at Arsenal in 2001 can often obscure the real reason that there was such a fuss about it: he was one of the best centre-backs in the world. He helped Arsene Wenger build his own great defence after George Graham's famous backline retired, spent five years at Arsenal (the first time), won two titles and was part of arguably the greatest team the Premier League has seen: the 2003-04 Invincibles. It was probably worth all the grief in the end.

2) Andrea Pirlo to Juventus

Mark van Bommel caused damage to plenty of midfields down the years, but unwittingly he might have caused the most damage to one of his own. Pirlo had been injured towards the end of the 2010-11 season while at AC Milan, but by the time he returned, the tactics had changed to the point the more robust figure of Van Bommel was favoured at the base of their midfield. So when the Milan board would offer him only a one-year extension (he wanted three years), Pirlo looked elsewhere and Juventus snapped him up. Juve legend Gianluigi Buffon called it "the signing of the century" and one of his generation's most gifted players went on to win four Scudetti and three more cups before moving to MLS in 2015.

1) Robert Lewandowski to Bayern

The saga of Lewandowski's departure from Borussia Dortmund dragged on for a couple of years, but when the Polish striker's agent said in 2013 that he would be leaving when his contract expired a year later, there was a grim inevitability about his destination. Bundesliga rivals Bayern had already landed Mario Gotze from Dortmund for €37m a year but their signing of Lewandowski in the summer of 2014 for nothing eclipsed it by miles. Since then he has scored 230 goals in 275 games, been Bundesliga's top scorer four times and been the spearhead of a team that has won the last five titles. Lewandowski is second in Bayern's all-time top goal scorer list, and while he won't haul in Gerd Muller (who scored a ludicrous 564), he's already putting distance between himself and is establishing himself as one of the greatest strikers ever.