Thanks to a recent explosion of online booking sites, the $24 billion short-term rental market is now about one-fifth of all U.S. hotel-room revenue, according to Alexis de Belloy, a vice president at HomeAway and VRBO. De Belloy’s sites, which are among the first generation of online rental agencies, cater mainly to families looking to book entire houses—a great way to save money on the road. The success of HomeAway and VRBO has helped to launch a slew of home-rental sites, many of which serve travelers with ever more particular tastes and interests. With listings in 10,000 cities and counting, AirBnB is like eBay for rentals: each host has a profile with user reviews and images. Plus, everyone is encouraged to submit ratings after a visit, which maintains quality control. Roomorama and iStopOver provide similar offerings, with additional features such as the ability to post requests for specific types of accommodations, in case you want, say, organic food in the fridge or a toddler-friendly apartment. And finally, taking the house-swapping trend to a whole new level is Luxe Home Swap, which lets you trade stays at your chic place with one of thousands of comparably stylish options across the globe for an annual fee of $159. At press time, a high-design house in Tucson, Arizona, and a relaxed beach retreat on Isla Fuerte, in Colombia, were just two of the properties available.