Stumbled across a couple of niche sites, that have supplemented their websites and revenue by using Zazzle? You create products using artwork or photos, and Zazzle handles printing, shipping and payment processing. The artist recieves a percentage or any sales generated. Seems this works quite well for niche sites. Check these out:

Horse Stall - Horse Themed Gifts
Dog Pound - Dog Themed Gifts
Golf Clubhouse - Golf Gifts

Original post by Frank Rumbauskas