Martial's initial fee is 36M£ (Negotiated in euro so 50 M euros) :
+ 7,35M£ (10M euros) If he plays more than 25 games (I don't know what means a game, if he plays full games or 1 minute)
+ 7,35M£ (10M euros) The moment he will reach the 10 caps with French National team (He can play twice this week for France)
+ 7,35M£ (10M euros) If he finishes in the top 20 of the Ballon d'or in the next 4 years.
Two things on the fee only.
Euro has dropped very deep recently meaning that the exchange rates are in favor of British when it comes to change. Unfortunately, all has been done in Euro and then converted in £
The initial fee for him was a bit overated to me. I won't throw a sum just to put one, but I guess that for 30M£ I would say ok. The bug here, are the two easy bonuses that will be given at Monaco. This is very reachable by Martial, meaning that the REAL fee paid by United for him would be 50M£