Americans love flea markets, which is why person-to-person auctions have become the most popular kind of auction on the Web. You never know what you'll find for sale, and you get to trade with others around the United States [other countries are coming online soon]. But in the excitement of buying that hard-to-find item, it's easy to forget that you're not doing business with a company whose toll-free number you can call if you have a problem. Instead, you're trading with a total stranger who may not be honest. Before you dive into the world of online auctions, where bids usually aren't retractable, take a spin through this mock auction on an imaginary site--AuctionMania--and familiarize yourself with the process. It's fun and easy, but there are some things you need to know before you commit your cash.