#4 Douglas Costa
Market Value: €55 million
Transfer Fee: €40 million
Difference: (€15 million)
Having spent last season on loan at Juventus from Bayern Munich, the Old Lady was quick to activate the option to buy Douglas Costa and make the transfer permanent for €40 million this summer.
The Brazilian played 31 times for the Italian champions last term, scoring four goals. He also had the most dribbles of any Serie A player last season (106) and the second-most assists (14). During his time at Juventus last season, his market value increased from €30 million to €55 million.
As Juventus try to build a team capable of winning the Champions League, they have secured a real bargain by getting the 27-year-old for a full €15 million less than his market value, even if they are responsible for the increase in his current value.