Investing in promise of youth
Just 18 when he moved from Everton to Manchester United for £25.6m, still the world record fee for a teenager, in the summer of 2004. Scored a hat-trick on his debut, and has not looked back since.
Signed for Atletico Madrid from Independiente aged 18 in 2006, for £20m. Aguero has scored 102 goals in 234 games for Los Colchoneros and has seen his transfer value soar.
Milan paid Internacional £21m for Pato even though he was just 17 in 2007. He has developed into a vital member of team that won Serie A last season.
Real Betis set a new world record when they spent £21.5m on Sao Paolo's 20-year-old Brazilian midfielder in 1998. Despite being a World Cup winner in 2002, his career was a huge disappointment, and he even failed to secure a contract with Bolton Wanderers after having a trial with them in 2009.
In 2001, current England manager Fabio Capello spent around £20m to bring the explosive 19-year-old striker from Bari to champions Roma. After five years of rows and controversy, Cassano was sold to Real Madrid for £4m. Has recently rebuilt his career with Milan.