every time i've skied an airbag it was free (if you bought a skipass)
that being said, if you haven't done backflips yet, try those, they're scary first time but easy once you've popped the cherry they become second nature. so an airbag is excellent to get over that first fear ....
also lincolns or misty 5s are pretty easy and safe on snow, so if you're looking for a "safe" flip these are pretty good options imho.... you can see the landing during the entire rotation and even if you don't get the entire rotation around, it's better under/over rotate on a lincoln/misty than on a front/backflip ....