Kayak.com

While sites such as Travelocity and Hotwire search only their own databases, Kayak searches over 100 airline websites, online travel agencies and other travel sites. This means that there is a better chance of getting the best fares when you use Kayak.com. Users can also get fare alerts and tailor searches according to required airlines, airports or dates. There is no fee for most bookings.

Most reviews suggest that travelers should start with the top-rated Kayak.com. Since Kayak.com functions as a meta-search engine, it is more comprehensive in seeking the best price. You can book directly through an airline, avoiding the service fees charged by travel websites like Orbitz, Expedia and Travelocity. In most cases, makes its money by receiving a kickback from the online travel agencies and through paid advertising. Kayak searches at least 120 different travel sites to come up with the best fares and hotel deals, so you’ll be sure not to miss a bargain.

The company was established in January 2004 by ex-founders of Orbitz, Travelocity, and Expedia. It is based in Norwalk, CT. Kayak.com has raised about $30 million since its establishment. The company is not a travel agency itself; it does not sell airline tickets, hotel rooms or rental car reservations on its own.