#2: Nathaniel Chalobah - £5m

Although midfielder Nathaniel Chalobah hasn’t done enough at Watford to be considered a major success just yet – he looked excellent in the early part of the 2017/18 season but suffered a knee injury in September and has been shelved since – but even if he simply goes on to be a serviceable player rather than living up to his potential as a great, the fee he was signed for remains insanely cheap.
Watford paid just £5m for the former Chelsea youth star – a bizarrely low price for a number of different reasons. Firstly Chalobah is just 23 years old, meaning he’s got at least a decade ahead of him; secondly despite not playing all that much at senior level, his youth record is exemplary and he’s the most capped player in the history of England’s age group sides, and thirdly, when compared to fees for similar players in 2017, the low price is literally jaw-dropping.
Consider that in the same summer transfer window, Chelsea spent £40m on Tiemoue Bakayoko and later on, £35m on Danny Drinkwater. Davy Klaassen cost Everton £23.6m, Roque Mesa moved to Swansea for £11m, Jacob Murphy to Newcastle for £12m, and well, you get the picture.
He might not have pulled up any trees just yet, but even if he’s a moderate success, the fee for such a talented youngster remains frighteningly cheap considering the climate he moved in.