What's wrong with paying 400k, Utd certainly have the money. Arsenal have been out of the CL for 5 years running so you can understand why the fans would want to stretch the limited budget so that we can get in some more players. But why would Utd be upset at paying over the odds for a genuinely good player. Would you rather believe that the money goes back to the Glazers.
For the record I believe a player with one World Cup, 4 Champions League titles. 3 La Liga Titles, 4 club World Cup, 1 Copa Del Ray on his last major contract moving from Real Madrid ( who, let's face it are bigger than Utd) is easily going to demand 400k. 400k is a conservative estimate. Partey got 250k and he moved from At Madrid to Arsenal, Varane is easily getting more. It's still a bargain for a player of Varanes quality so I don't know why anyone should be upset.