As a professional face painter, I highly agree that face painting is a great fundraiser. However, it can be dangerous if you do not use the right products. Whatever you do, do not use acrylic paints.They can burn the skin and leave scars. Palmer's liquid paints and grease paints are also something that you should shy away from. While cheap, they will be really hard to work with and will be extremely messy. I recommend purchasing a small water activated kit from Snazzaroo. Below is a link to where you can purchase one, as well a link to where you can purchase the proper sponges at a reasonable price. Buy a pack of Loew Cornell brushes from your local craft store using a coupon, and you should be set. You can also look on youtube for how tos of the most popular designs.
Good luck on your fundraising!
http://www.facepaintforumshop.com/servlet/the-51/Snaz-Rainbow-Palette/Detail