How much do venues pay for MMA fights?

Does anybody know how much a standard booking fee for an event like King of the Cage would be at an American Indian casino?

What about other venues?

Source: http://www.mmaforum.com/other-mma-amateur-mma/106362-how-much-do-venues-pay-mma-fights.html

Rashad Evans Urijah Faber Wagnney Fabiano Kevin Kimbo Slice Ferguson Paulo Filho