I've taken an airbrush class here at RIT. Yes, I had to give them $80 as deposit for using their airbrush. I had to take good care of it and have it returned by the end of the quarter. I did that, and got my $80 back.
As for the class itself, it was easy. We started with learning how to use the airbrush. We then moved on with simple stuff like dots. lines. circles, etc. We then moved on to gradients, edging, in-out edging, etc. We finally were assigned an art project which we had to create something that uses airbrush painting. I repainted a South Park "World Is Not Enough" spoof. A friend of mine painted his Robotech 12-inch figurine. One guy in my class painted a picture of U-51. Another guy painted a t-shirt design with the nose-picking boy from Simpsons. Finally, one guy did a realy good job of painting a naked woman... and yes, it looked almost real. Many of us got an A in the course.