Another idea. During Homecoming (or Rival week) we sold spirit chains. $.05 a link. Each class had their own chain hanging from the ceiling (high ceilings). (The rivalry was if someone donated a penny, it removed a link, wasn't always used.) Use your school colors. Each class gets a color, seniors can use all of the colors. Your expenses will be small. Construction paper, tape or staples, string (for hanging from the ceiling and jars to collect the money.) And someone to stand on a ladder.