I've been to 2, both on the same night, it was my home boy's 18th birthday (this was 4 years ago)...
I didn't spend much, but it wasn't worth it. I could smoke a blunt and watch a movie and be just as entertained...plus, 95% of those girls either have an STD or are complete gold digging skanks. But some people like that shit, I'm just not one of them.