Beyonce, Lady Gaga, Prince, Michael Jackson, Red Hot Chili Peppers, all got paid the same rate to perform their sets at the Super Bowl Half Time Show: zip. Zilch. Goose egg. Nada. Nothing.
The dancers and production staff get paid for their work, but the artists are paid in exposure. Which does sort of seem like a load of crap given how much money these companies make off the performers, but it's not like any of them are hurting if they're being asked to perform for one of the biggest events in the world.