#5 Arsenal
It's not often you see Arsenal high up in any spending lists, but Arsene Wenger has broken the club's transfer record in two consecutive windows for Alexandre Lacazette and Pierre-Emerick Aubameyang. The Gabonese striker arrived from Borussia Dortmund for an eye-watering €63.75 million, although the Henrikh Mkhitaryan-Alexis Sanchez swap did not dent Arsenal's finances.
Konstantinos Mavropanos's signing brought Arsenal's total spending in January to 65.85 million.
It wouldn't be Arsenal without them raising money from player sales, and with the departures of Theo Walcott, Olivier Giroud, Mathieu Debuchy and Francis Coquelin, the Gunners raised €53.5 million. Net-spend is pretty much a meme when it comes to Arsenal, although €12.35 is a decent amount.