Bupkiss. Even at 12-0 if you haven't broken free of the regional scene and you're not specifically putting asses in seats with your own cheering section loudly proclaiming they bought a ticket just to see you, nobody is paying you much. (ie enough that you don't still need a full time job)
if u ask Pac how much was he making in his first fights u wont believe it. on the other hand an olimpic gold turning pro is a different story. keep in mind there are/were lots of fighters going into title fights still having regular jobs.
Where do we sign up? I've seen debuting fighters not take home 500 for a 3 rd tournament. 500 might be their purse, but licensing fees, sanctioning fees, trainers take and mgrs take gets a debuting fighter or scrub about 160 bucks for 4 rds if he survives.
If you fight on TV sometimes you're actually paying out of pocket to be seen on television (including traveling/hotel/corner expenses). Like if you get paid $150 but the plane ticket alone was $250 lol