How to bet on the UFC - Question

Was at Mandalay Bay and saw Tito Ortiz's odds for the fight were -150. I heard that it means that if you bet $150, you get $100 back. My question is, do you only get $100 back or do you get $100 back plus your initial $150 for a total of $250?

That's what I thought but I thought maybe that was Vegas's way of saying..."this guy is so favored you can't bet on him." Of course Vegas won't say no to your bet.

Ok, cause I bet $100 on Tito and my ticket says "$100 MLB TO WIN $66.65." I was confused because I thought it would have said $166.65...not just $66.65.