British? I think it's about 30-40 pounds which you get back after having 5 fights (they've made money back from clubs paying to host bouts by then you see... in theory... ).

They get money from 2 main things:

Fighters who don't make it past 4 fights and clubs that are willing to pay for the officials to come out and all teh rest of it because they makea shit load on entry fees and drinks...