There seems to be two sides to the argument:
1) The fighters knowingly and willingly sign a contract and they're income is more than made up in sponsorship money, bonuses, and non-disclosed income.
2) The UFC makes a lot of money per event and it's unethical to not pay fighters more.
I'm firmly in camp 2. The reasons the first viewpoint bothers me can be broken down to guaranteed money vs. possible money. A fighter, on the low end, in the UFC gets contract at 6K/6K. Assuming the fighter stays active and fights 4 times, that's a range of 24K-48K, neither of which is easy and/or viable (depending on wher you live) to raise a fmaily on and that's before you factor in training/ lifestyle expenses of a professional athlete. It is possible tha they've recieved bonuses and enough sponsorship money to make up the shortfall, but in the end, that's extra, it's possible money. It's "tip" money. It's a similiar situation where we (US Society) pay food servers under minimum wage and expect them to make it up in "tips" and/ or the kindness of strangers. It may be legal, but it's unethical.
So, I decided to do some math. MMAPayout.com Blue Book has a nifty list going back to 2006 of the buys for UFC PPV's. I copied everything into a spreadsheet, ran some averages, and a hypothetical situation. There are definitely some errors in my assumptions, but I'm not a math person or statistics person to try and accommodate for those and could not find the information I needed to adjust. I'm happy to be up front about those assumptions.
The average PPV buy from 06-present is 509,628 buys per show, including the canceled UFC 151. I divided that in half and assumed that half the buys are SD and half HD coming up with $12,727,951 and $14,002,020 respectively, totalling $26,729,971 in revenue just on PPV. There is an error here I don't know how to account for in that I'm not positive that a lot of HD buys were made in the early half of these dates as it wasn't as prevalent in homes. All in all, Per year, staring from 06, the UFC "made" $267,299,707.45, $294,029,678.19, $320,759,648.94, $347,489,619.68, $400,949,561.17, $427,679,531.91, $374,219,590.43, $106,919,882.98, totalling $2,539,347,220.74. Think about that...$2.5B in 6 years.
This doesn't include sponsor money, advertising, gate sales, etc., just PPV.
$2.5B and they're paying a guy 6K to show and 6K to win. Dana White has never missed an oppurtunity to tell us we're wrong, so I'm hoping he starts disclosing some real figures, but the silence is telling to me.
In my humble opinion, if they paid these guys a living wage, enough to cover professional expenses and take care of the family over the course of 3-4 fights, the UFC product would vastly improve. These men and women aren't dogs who you can starve long enough to make them viscious. They're people. They're human beings trying to make a living doing something they love, getting beat up to entertain us, and hoping to catch the break to take care of their families their future. We as fans owe it to them to support higher pay. That is the only thical stance. It's the least we can do.