10. Gianlugi Lentini - £13m | Torino to AC Milan in 1992
Lentini moved to AC Milan in 1992 for a hefty price tag. As is often the case, with such a significant outlay hanging over a player's head, those in question tend to struggle to deal with the weight of expectations firmly on their shoulders - take Lentini as case in point.
That said, he was involved in a car crash that interrupted his career, so you forgive him for not reaching the lofty heights that were initially expected.