Manchester United have so far completed the most notable transfers.
Jose Mourinho bought the likes of Eric Bailly, Zlatan Ibrahimovic and Henrikh Mkhitaryan.
Arsenal signed Granit Xhaka, Liverpool took Sadio Mane away from Southampton and Chelsea hijacked Michy Batshuayi from Tottenham and Crystal Palace.
But which one of them cost the most?
Check out our gallery above for more.