Do your homework before you head down to the used car lot. Here's help. By the editors of Kiplinger's Personal Finance Updated January 2015 Buying a used car is a great way to keep costs down when purchasing a vehicle. And with the option of certified pre-owned autos, you can cut some of the risk out of buying used and get some new car perks.See Our Slide Show: 10 Best Values in Used Cars, 2014 But before rushing down to the showroom, arm yourself with the pricing and safety information you'll need to avoid the lemons. The resources and steps outlined below will help you research a used car quickly and thoroughly. Settle on a Price There are several Web sites that help you find the going rate for used vehicles. Most offer several prices including, retail, trade-in and private party. If you're shopping for a car, look for retail value -- what you can expect to pay at a dealership. The trade-in value is what you'll get for a car you sell to the dealer. Don't expect to get retail value for your trade-in vehicle. That's because the dealer will spend money to improve its condition before reselling it and wants to make a profit, too. Sponsored Content Because used car prices vary widely depending on condition and mileage. Use at least two or three of these sources to develop a reasonable price range. Advertisement Edmunds.com: Lists retail, private party and trade-in values. Edmunds' True Market Value reflects actual dealer sales from across the country, factoring in inventory levels, economic trends, local market conditions and unpublished incentives. Kelley Blue Book: Provides retail, private sale and trade-in values. KBB's editors monitor the wholesale market, rental car companies, dealerships and financial institutions to derive values. The site does not provide values for vehicles more than 20 years old, but it does factor in condition when estimating values. NadaGuides.com: Find the retail or trade-in value on vehicles. The values from NADA are based on information gathered from new- and used-car dealers, auto shows, trade periodicals, vehicle classifieds, magazines, newspapers, advisory boards, associations, and car clubs. Edmunds and Kelley Blue Book provide used car listings in addition to values. You can also search Cars.com or AutoTrader.com ffor used cars on sale throughout the country. Visit manufacturers' Web sites for a listing of their certified-used-car inventory and prices. Advertisement You likely will find discrepancies from guide to guide. Retail values tend to run higher on Kelley Blue Book, while trade-in values are typically lower than other guides. Banks and credit unions in different parts of the country also tend to rely on different guides, so find out which guide your lender uses. If you pay more than your banker expects, he might not finance the entire amount. Go Shopping Start your search online at AutoTrader.com or Cars.com, which list private sales and vehicles at dealerships. You can search nationwide or just in your area and narrow by the features and mileage you’re looking for. These aggregator sites will also list “certified pre-owned” vehicles. It's as close to buying new as you can get. To be certified, low-mileage, late-model vehicles must pass a 110- to 300-point plus inspection, depending on the manufacturer. Warranty lengths will vary by manufacturer, but generally cover major driveline components. Advertisement Do Your Homework Research is the key to getting a deal on a used car. Once you've found the car you might buy, check its history and safety record. History. Get the VIN, or vehicle identification number, to check a car's history at Carfax ($40 for one report, $50 for five, or $55 for unlimited reports) or Auto Check ($30 for one report or $45 for unlimited reports). Be on the lookout for a mileage discrepancy or a salvage/junk record. Also note if the car has crossed state lines. State salvage laws vary, and a state-to-state move could be an attempt to hide problems. The government's National Motor Vehicle Title Information System also compiles information related to fraud and theft including title and salvage data that's required by law to be reported. You can purchase an NMVTIS report through partner companies listed on the site (prices vary). Consumer Reports provides reliability histories on used cars based on surveys of thousands of car owners. The survey results are published each April in the magazine and are available to online subscribers. Safety record. Crash-test results, consumer complaints and manufacturer's technical bulletins, which alert dealers to problems, can all be found at the National Highway Traffic Safety Administration's Web site. Research won't guarantee that you'll find every problem with a car, but it will help you steer clear of a clunker.