Upscale furniture. Luxury cars. Even fancy vacation homes. After years of shunning the online trading market, owners of bigger and higher-end products are turning to the Web in search of swap partners. Indeed, a host of new sites have sprung up to connect would-be traders, and the action is heating up on popular swap hubs; online marketplace Craigslist.org, for instance, saw bartering posts spike by 80 percent over the past two years. But as always, buyer-er, swapper-beware. Our take on the most popular swaps:

Check out of the hotel

Home swapping, once a fringe option for affordable vacationing, is moving into the mainstream; a recent survey by travel Web site TripAdvisor found that 43 percent of respondents say they would now consider a house swap. Interested travelers can surf sites like HomeExchange.com and ExclusiveExchanges.com to browse listings, read reviews and (hopefully) find the right trade partner. The catch? Sites can charge as much as $2,500 to join and often do little to screen listings.

Ditch the extra car

Traditionally, getting out of a car lease has been "almost impossible," says Jack Gillis, director of public affairs at the Consumer Federation of America. But these days, people are beginning to go online to unload their leases-or to snap up a good deal from someone else. One caveat: Most sites require that both parties pay a fee; LeaseTrader, for instance, charges $90 for a listing fee, $40 per membership and credit check, plus $150 for the company to handle the paperwork.

Clean out the garage

When it comes to swapping household items, experts suggest starting with an appropriate niche site, like Zwaggle for strollers, cribs and other kiddie gear, or Swaptree for music, books and DVDs. The most popular online trades-and thus the best selection of stuff-tend to center around smaller goods that are easy to mail, says Mark Hexamer, Swaptree's VP of marketing. For bigger items like furniture, using local sites like Craigslist eliminates the hassles of shipping. But forget about being too picky: Traders may need to settle for "a couch rather than a 'brown couch,'" says Hexamer.