Each case & club can be different but there are normally three types of expenses that fees pay for:
1) Field rentals
2) Coach(s)
3) Club/Org admin
Some clubs wants/request coaches have a minimum number of players per team say 16 for 11v11 and they don't have much choice in the matter. Others offer more flexibility.
Expenses #1-2 can vary widely depending on how much/type of field space, games played, and the level/experience of the coaches. The one price fits all deal is kind of comedy but I guess their trying to spread the costs out wider so what you pay for may or may not be what you get but that's the rub about "clubs"