This is what I finally came up with. We took an extra 5 gallon water bottle and covered it in martial arts paper I found at the local scrapbook store. Then I added a strip of black card stock over that to add my letters. I finished off the bottle by adding some of the cute Stampabilities karate images to both sides.
It's hard to see in the picture, but it's working already! On Saturday we put it out on the counter during the competition team practices and people started putting in their loose change. It was a real attention getter too. Since it is fairly empty, when you drop in your coins it makes a VERY loud noise - almost like a shot gun sound. Once one person started putting in their coins, everyone followed.