Keats the methods of payment are normally.
Appearance fee - self explanitory
Win Bonus - as above
KO bonus - just offering an additional bonus as an added incentive to perhaps stop fighters from cruising for a victory on points.
KO bonuses are probably not that pheasiable accross the board as 90% of the bouts are ending within duration. As the sport grows these will ad a bit of excitement.
I know Tarik (as an eg) offers a headkick KO bonus to liven up the events.
Sales incentives are paramount IMO as it lets me see who is worth what.
Justin