Buying a car or truck at auction, either online or offline, can be a great way to save a bundle on a car. From police auctions to tow companies selling off their abandoned vehicles to wholesalers dumping car stock, auctions can offer great bargains.

However, be prepared to buy a car “as is” and don’t expect an auction car to come with a manufacturer’s certification, warranty or a lot of nice accessories.

To get the best deals at car auctions, both online and offline, keep reading for five great tips that will protect you as a consumer and save you big money.

1. Pre-Register for Local Auctions

Most local, in-person auctions require you to pre-register. You’ll be supplied with an information booklet about the vehicles, instructions on how to bid, the rules of the auction house and information on how to pay for your purchase. Read over the auction rules thoroughly to avoid mis-bidding.

2. Take Your Time at the Viewing

Don’t show up at a car auction minutes before the bidding starts. Rather, take advantage of the viewing opportunities and give yourself time to inspect the cars that interest you.

If you’re not overly experienced with cars, either convince a mechanic friend or hire a mechanic to come with you to help you evaluate vehicles and track down some of the better deals.

3. Set a Spending Limit

Before you even set foot on an auction lot, set a personal bidding limit. If you’re bidding on a particular car or model, bring along a printout of its Kelley Blue Book values. That way you won’t start overbidding and pay too much for a vehicle that’s simply not worth it.

4. When Buying Online, Know the Terms and Guaranties

Online auctions are a little bit trickier because you’re trusting a company with thousands of your dollars. Popular sites like eBay offer a certain amount of buyer protection up to $25,000, but only for particular types of fraud - particularly title fraud, stolen vehicles, odometer fraud, undisclosed salvage or flood damage, and non-delivery of the vehicle.

5. When Buying Online, Have the Car Inspected

If you’re buying a car through an online auction and having it shipped to you, have it inspected by a third-party mechanic. Call up mechanics in the area and arrange to hire one to go to the car and look it over. This will obviously cost you a couple of hundred dollars, but it could save you thousands - as well as some degree of your sanity - in the long term.