Will Barker began selling stylish belt buckles on eBay two years ago and watched his sales take off, peaking at $4,000/month by late 2006. But Barker was curious about Amazon's third-party stores, and in February 2007 he took the plunge, opening an Amazon outpost.

The numbers still astound him. From initial sales of $400 in his first month on Amazon, Barker's sales have skyrocketed, totaling more than $11,000 in December.

"It was like a runaway train," he says. "I didn't know that many people bought belt buckles."

Barker's success on Amazon made eBay more and more of a hassle. While eBay items require individual listing, Barker can keep an inventory in his Amazon store, a better fit for his business model. Shipping records and logistics are also more streamlined with Amazon, Barker says.

Barker is currently working on building his own destination site, BarkersBuckles.com, and plans to eventually expand into apparel and other items. Whatever direction his businesses grows in next, he plans to do it with Amazon: "If I could do nothing but sell through there, I'd be happy."