Average Salary: $34,000
Expected Lifetime Earnings: $1,419,432
The top UFC fighters can make a ridiculous amount of money for a single fight—especially if it's such a big deal that it's televised on a pay-per-view with a number in the title.
For the men and women at the top, they might be looking at a base salary of a few hundred-grand for the win, plus thousands more in knockout, submission, or "Main Event" bonuses, and potentially hundreds of thousands more in "back room" bonuses (source).
These guys and gals are also probably going to have a number of sponsorship or endorsement deals. At the end of the day, a martial artist may be taking home more than a million bucks for a single fight—not as much as a boxer at the top of his game, but way more than the dude down at your local dojo.
Of course, those are the exceptions rather than the rule. There can only be one champion and a few contenders. Below them you have your second-tier fighters, who usually bring in between $10,000 and $25,000 for each fight. This mid-card level is not a bad place to be, although it means you're either still coming up or not making a habit of winning.
Unfortunately, to even push along in the mid-card will take a lot of luck and determination, not to mention a slot in one of the more professional leagues. Most likely you'll work nonstop to book a fight once every few months, for which you'll get paid a few grand, plus another few grand if you win. Then comes all the money taken away from you for insurance, licenses, taxes, manager and promoter fees, etc.
Do you really want to put yourself through all of this train and paining—sorry, pain and training—if you're only going to be fighting to try to make it above the poverty line every month? Maybe you should try getting people to pay you for hugs instead.