Q: Peter, Which websites are best to compare the cost of flights to a particular city in the United States?

—Dona Hall, Carmichael, Calif.

A: Fortunately for travelers, Dona, quite a few websites can help you compare and save on flights. Some of my favorites include FareCompare.com, Kayak.com and Bing.com. All can help you make informed flight purchases, but each one has its own special features that focus on fine-tuning your airfare search specifically as opposed to a broader approach to all travel (hotels, car rentals, etc.).

Kayak’s flight search allows you to easily compare flights from any airline. Plus, it gives you the option to compare these rates with top deals found on the major aggregators like Expedia, Orbitz, Travelocity and others. Once your search results are found, you can narrow down your options based on your preferences — such as price, flight time and aircraft type.

Kayak also has an “Explore” feature that helps you come up with your perfect vacation destination based on your input. You specify how much you’re willing to spend on flights, the climate you want to enjoy, what activities you prefer and how long of a flight you’re willing to take. Kayak will then supply you with a map of your ideal vacation spots.

Bing is similar to Kayak in its flight search, but it does offer the unique feature of “Price Predictor." After searching for a particular flight, this fare-casting feature will advise you to either buy your ticket if prices are rising or hold off if prices are expected to fall. Bing claims to be 75 percent accurate in its predictions, so it may prove useful when deciding to make a purchase.

FareCompare differs from Kayak and Bing in that it specializes only in flights. While it doesn’t give you deals on hotels or car rentals, it can give you the most thorough and up-to-date information on flights. Like the other two websites, FareCompare offers a flight search that lets you easily compare ticket prices from airlines and online travel companies.

FareCompare does not stop there, however. If your flight dates are flexible or you often travel the same route, check out FareCompare’s “When-to-Fly alerts." This feature allows you to save your favorite flight destinations, and FareCompare will send e-mail alerts the instant prices change for this flight route. FareCompare also publishes tips on avoiding certain airline fees, comparing baggage fees, traveling with children and more.

Finally, the AARP Travel Center powered by Expedia offers the useful Trend Tracker tool. Trend Tracker lets you evaluate the least expensive hotel and flight prices for the time you want to travel. Compare historical price and weather trends to get the best value on both your hotel and flight bookings.

With so many free online resources, there is no reason you should be making uninformed airfare purchases. Do a little research and you’re bound to find flight prices that’ll fit your budget.