By now, you know that no single travel Web site always offers the lowest prices. So each time you book a trip online, you feel you have to check several sites to assure yourself you're not overpaying.
Save time by using sites or software that employ "Web-scraping" technology to simultaneously search multiple sites and then present prices in easy-to-read charts, making comparison shopping a snap.
Sidestep.com: SideStep is a free program that you download. Its search engine automatically launches when you shop for air, hotel or car rental fares, scouring multiple travel booking sites (including low-fare carriers that don't always appear on sites, like Expedia or Orbitz) for the lowest prices. While you can't book your trip directly with SideStep, it will provide a link to the page where your deal of choice is located.
Itasoftware.com: Cambridge, Massachusetts-based ITA Software helps travel suppliers develop online booking sites, but it also offers consumers a broad and flexible airfare search engine on its home page (see the "Looking for Airfares" box.) You can check one-way, multisegment, or even international fares for flights originating overseas. It also searches fares for airports within a 300-mile radius of your origin or destination, or flights within 24 hours of the flight times you specify.
Travelaxe.com: Like SideStep, this isn't an actual booking site, but a small program you download that searches multiple hotel-booking sites for the best rates in more than 58 countries. The end result is an exhaustive array of rates with the lowest ones highlighted. To limit the search results in a huge hotel market like New York City, you can enable filters that specify the distance from the city center, price or star rating. Once you've found the best rate, TravelAxe provides a link to the site, where you can make a reservation.
Chris McGinnis, travel correspondent for CNN Headline News, is author of The Unofficial Business Travelers' Pocket Guide.