Buying secondhand cars is a risky business, with more complaints about used cars than any other category of product in the UK in 2013. There were around 84,000 complaints about secondhand cars in the UK alone in the first ten months of the same year- so in a marketplace where the buyer really does have to beware, what can you do to beat the dodgy dealers and grab yourself a genuine bargain?Do Your ResearchAs with any major purchase, it’s best not to rush in. Do your homework first- how much do cars like the one you have your eye on normally go for? Check genuine reviews of the cars on consumers’ forums online, and ask questions (don’t just read the marketers’ hype- find genuine customers online and find out what they think of their cars). Remember too that the bigger the engine, the higher the running costs will be, including insurance and petrol, so that will need to be factored in if you’re looking for a bargain in the long term.Choose Your AuctioneBay auctions are popular ways to buy many types of goods, including used cars. If you do use eBay, the famous “eBay guarantee” promises that you will get the item you paid for, or you will get your money back. This is an important protection in a notoriously risky purchase.Before paying, it’s definitely best to check the car over in person, and examine the documents the seller provides (including their ID). If you don’t know much about cars, take someone with you who does. There are numerous tutorials and tips to be found online to help you ask the right questions.Keep Your CoolAuctions are exciting, and in the heat of the moment it’s totally possible to get carried away and pay more than you should. Be disciplined: use the research you’ve done to find out the car’s true market value, and don’t pay over the odds. If you’ve never purchased anything at auction before, it might be worthwhile attending one just as a spectator to get a feel for the whole thing before you attempt to buy.The Citizens’ Advice Bureau has lots of information available to let you know your rights when you buy anything at an auction, but bear in mind that some auction houses have certain rules which exempt them from the Sales of Goods Act. Check the rules carefully before you bid.