Basicly i am starting a man utd save, i have my eye on quite a few players. My plan is to buy every i need in the first season i wont be able to do that without monthly installments.

My question is 2 or 3 of the players i think could benfit a season of first team football at their current clubs so if i put the bid in for the player to come at the end of the season, when do i start paying for the player. Is it when he agrees terms or when he joins the club at the end of the season and how is the transfare budget effected.