At my senior year prom, we had a girl give birth in the bathroom (I know, cliche), five kids snuck in beer and got drunk (which when i tell people form other highschools must be some low number I guess), and we had the cops called in about an hour and fifteen into the five hour affair (we had long proms) when a group of men got into a fight and busted each other open using brass knuckles and rings (and I think one had a knife), resulting in one in critical condition, and all of them needing some number of stitches.
... Which is why I'm glad I didnt go. Isntead, my friends and I decided that we would dress a little nice (nice jeans, a nice button up shirt, hair managed, tennis shoes, etc), went out to the movies, some bowling, stopped in on the dunken Donuts and then went to the parking lot of an Eat n Park while it was closing and had a radio play as we all just danced.
the price difference? well, lets see. it would have cost 120 (american) dollars for a pair of tickets, if you didnt have a tux, almost 80 for the whole suit get up, However much you spent in gas to get there, and the optional after "party" at a hotel would have ran probably 89 dollars for a pair that night. So thats (about for me) 310 dollars.
the night I had instead, a little under 50 dollars total.
So yeah, iw ould suggets just not going and doing something fun otuside of prom instead, but thats just me.