How Many Party Favors To Buy For Teen Dance Party?

I am having a dance party for about 50 13-year-olds, mostly girls, in my basement and they will be having contests and games and we want to give cheap favors like plastic gangster hats, beads and feather boas. Do we need to buy one of each for every attendee? Or can we get away with just enough boas, say, for the girls and primarily hats for the boys?
Posted by Ellen Fix; updated 09/15/06