Our high school did anual "fun-walks", which raised money for the school.

I remember one year in particular, I probably didn't raise more than £4 or £5 (with sponsor forms), but I probably spent about £15 on my costume; I hired a Darth Vader one, complete with cape and mask.
For anyone who's never tried one of those masks, don't. They get hot and sweaty within minutes. I would have hated to be David Prowse, who somehow managed to wear a mask for 3 movies...lol.