What is the average salary for an mma fighter?

In short - not as much as their UFC counterparts. UFC is the biggest MMA promotion in the world and the fighters there get paid nicely. The newer guys may not make as much money as the established names, but a talented fighter can easily earn a six digit salary with the UFC every year. The other MMA promotions may not pay as much. Fighters usually earn a few thousand dollars per fight and getting a 5 digit pay out for a fight is a big deal in smaller promotions.