Transfer: Juventus to Arsenal, 1999
Price: £10.5 million
Impact: After just half a season at Juventus, Arsene Wenger snapped up the gangly winger who he had worked with previously at Monaco. Henry became the new prototype for a footballer, and scored a club record 174 goals from 254 matches.
Money well spent? In simple terms, Arsenal made a £5.5 million profit when Henry was sold to Barcelona last year. But the North Londoners benefited far beyond financial means: Henry was centerpiece of the continental revolution in England headed by Arsenal and help make Arsenal sexy.

Transfer: Sporting Lisbon to Manchester United, 2003
Price: £12 million
Impact: Cristiano Ronaldo has scored more than a goal every three games for Manchester United, and was central in his side’s run to last season’s title. He is among the top two or three players in the world.
Money well spent? Though his fee was high for an unproven teenager, Ronaldo has improved year after year at Old Trafford. If sold today, it would not be for less than three times the amount United paid for him.

Transfer: Brondby to Manchester United, 1991
Price: £505k
Impact: The Great Dane won 10 major honours at Manchester United during the 1990s. He never lost a Manchester derby (even for City when he played there in 2002/03!). In Alex Ferguson’s first league success in 1992/93, Schmeichel kept 22 clean sheets.
Money well spent? Alex Ferguson himself has called him the “bargain of the century”. He was 5th in both FIFA World and European Footballer of the Year and in 1992 and 4th in FIFA World Player of the Year in 1993. A goalkeeper! 4th!

Transfer: Southampton to Blackburn, 1992
Price: £3.6 million
Impact: Shearer scored 112 Premiership goals for Blackburn in 138 appearances and won them the title in 1995. This came as a small surprise as he had never been prolific at Southampton, scoring just 23 goals in five seasons.
Money well spent? A bargain at £3.6 million even in those days, Blackburn bought low and sold high when in 1996 let Shearer move to Newcastle for £15 million. The Premier League title? That was just a bonus.