Countless lists have been produced about big-money transfer flops - but what about the big-money transfer triumphs?
We all know Chelsea spent far too much on Fernando Torres, Real Madrid paid a fortune for Kaka at the wrong time and Barcelona wasted just as much money on the divisive Zlatan Ibrahimovic.
What we know less about are the success stories.
In order to qualify for this top five, the players in question had to be bought for at least £20m and stayed at their clubs for at least two seasons.
So, sorry Arsenal fans, although Mesut Ozil has made a promising start to life at the Emirates Stadium, there's still a chance - however slim - that he won't be a success in the Premier League.
Similarly with the world's most expensive footballer, Gareth Bale, who has only made two appearances for Real Madrid so far.
Click next to see the selected five.