If you’re looking into buying a used car, few things are as important as the history of the vehicle in question. (Obviously, such things as finances are also extremely important also–but the vehicle history can determine or influence the price of the vehicle, so don’t put yourself or your money at risk!)

Few buyers outside of junk and scrap yards want to buy vehicles with a long history of coming to pieces at all the wrong times, but the average used vehicle buyer might not be able to identify such a vehicle just by looking at it or even by test-driving it.

For that reason, services like CARFAX, CarStatusCheck and AutoCheck are highly valuable resources for potential buyers. Don’t be the buyer who doesn’t bother learning about their potential purchase. You could be putting yourself or your loved ones in danger.

The most common method of identifying a vehicle in order to perform a vehicle history check is with the Vehicle Identification Number, or VIN. This 17-digit code is unique to each vehicle and can usually be easily traced backwards through previous owners to discover the history of the vehicle.

VINs are usually found on the driver’s side of the car, near the bottom corner of the windshield. You can also look for them inside the driver’s side doorframe. Make sure to ask your seller for the VIN as soon as you can–whether over the phone, via email, or in person–and check it through the service of your choice.

When you get the vehicle’s history report, there are some very important things to keep an eye out for: things like salvage titles, repairs and maintenance performed, mileage, and accidents. A salvage title designates the vehicle as one that was declared a total loss (or “totaled”) by an insurance company and sold or given to a junk or scrap yard, which later reconstructed the car and sold it.

For a vehicle to be totaled, the cost to repair it must be greater than the worth of the vehicle as a whole. Salvaged vehicles have often suffered severe structural damage or other trauma, and such vehicles rarely perform as well as their non-salvaged counterparts and their re-sell value is significantly lower. So, if you do end up purchasing a vehicle with a salvage title, expect to have it for a very long time.

So, how exactly do vehicle history reports work? And, possibly more importantly, how much do they cost?

As with any service, prices vary: CARFAX charges $39.99 for a single report, while AutoCheck only charges $29.99. However, there are multiple options for payment: both of these websites, and probably others also, allow you the option to pay a slightly higher fee to run more than one VIN through their systems at a time.

$44.99 buys you unlimited reports for a whole month from AutoCheck, and $49.99 can get you 5 reports from CARFAX. (Unlimited CARFAX reports for a month cost $54.99, so clearly AutoCheck has the better deal there, but you should purchase reports based on your own needs.)

After purchasing the report, you can review it on your computer and print it, if you wish to do so. (Taking a copy to show to the seller can sometimes be a good idea.)

As previously mentioned, these reports are a must-have for the used vehicle shopper. For a more extensive list of vehicle history services, look online or ask any automotively inclined friends or acquaintances you may have.

Tony Wild is all about classic motorbikes and cars and not only blogs about them, but also restores them in his spare time.