Anderson - Porto to Manchester United - €30m / £20m

When Manchester United tried to sign Anderson from Porto in 2007, they saw their work permit application turned down due to a lack of experience. United argued that at 19, it was impossible for him to have any more experience having helped Porto to back-to-back Primeira Liga titles. The application was successful, but Anderson's time at Old Trafford was not as good as expected, despite playing over 100 Premier League games