The market for used music is well established. But now anyone with an iPod and a computer can easily buy a CD, make a digital copy, and then sell it online. Last year, a New Jersey record store launched a "Buy It, Burn It, Return It" promotion, encouraging customers to make copies of their CDs and return them for a 70 percent credit.
Old versions of Microsoft Office are always in mint condition and prices tend to drop dramatically when a new edition is released. Used software is heavily traded on eBay and Amazon.com: A 2002 edition of Office XP Pro was recently going for $207, well below the original price of $499.
Ten years ago the idea of buying a used watch from an unauthorized retailer might have seemed shady. But luxury auction sites like Portero remove the risk (and the gnawing suspicion you're buying something that fell off a truck) by guaranteeing the authenticity of purchases and emphasizing a high level of customer service.
Believe it or not, there is a small but growing market for used cloth diapers. That Fat Baby, a Web retailer based in Yates City, Illinois, lists dozens of styles and sizes-- including a terry cloth model with red trim and "light to moderate staining" priced at $4 plus shipping.
Seattle-based Bag Borrow or Steal allows fashionistas to cycle through new handbags as often as they want. For a monthly fee of up to $285 (plus insurance and postage), you get unlimited access to the latest bags from over 100 high-end brands, including Marc Jacobs and Chloé. Buying to own is so last century.