Retail Me Not has a Twitter contest going on right now with much bigger prizes than those offered by Whole Foods. Tweet your best money saving tip with the tag #retailmenot. They are giving away one $500 Macys gift card each day. The top tip will be picked at the end. That winner gets a $1,000 gift card to Macys. This contest combines an online only business with a physical store. Notice that the contest should seek submissions that relate to your kind of business.