1) Check the price of other cars in the market. Do this by looking at various websites on the internet.
2) Don't buy the first car you see. Shop around, there are plenty of cars in the market but not enough money around, so don't part away with your money so easily.
3) Check the car thoroughly for wear and tear. Check the carpets, drivers seat, gear stick handle/cover, foot pedals, door panels and steering wheel for wear and tear. These parts will look well used or worn out on high mileage cars. Some cars have had their mileage lowered illegally, but looking at the wear and tear of the car shows the true mileage of the car.
4) Find out if the car has been in an accident and repaired by looking for unevenly matched gaps in the body work panels. All the gaps in between the panels should be the same size on both sides of the car. For example where the bonnet sits, the gap on the right next to the wing should be the same size as the gap on the left. If one gap is much bigger than the other or it's twisted in anyway, it's probably been repaired...
5) Check the paint colour is the same shade on all panels of the car. Touch the body panels, does the paintwork feel rough? Rough paintwork is a sign the car has been resprayed. Look at the rubber on the windows, is there any spray paint on them? Quick re-spray jobs just cover the car up with masking tape so you can see the paint colour sometimes on the window rubber or on other parts of the car such as the bumper, head lights etc.
6) Check the tyres. Do all the tyres match? If the front tyres are worn out in the inner or outer edges, the tracking may be faulty. Odd tyres shows the car has probably done a lot of miles.
7) Open the bonnet. Look under the engine and check the chassis is straight on both sides of the engine. It could be bent from an accident.
8) Open the engine oil cap under the bonnet and look inside. If the engine oil is white, the head gasket is blown(expensive to repair). Check the oil level, if it is too high or too low, the car has obviously been neglected. Also ask when it was lasted serviced and how regularly it has been serviced.
9) Drive the car. When you drive it, make sure the stereo is turned off. Don't chat to the seller, just listen to the engine run and listen out for odd sounding noises. If it is automatic, make sure all the gears change at a smooth speed and in time. Make sure the car drives in a straight line (doesn't pull to one side) and the steering doesn't shake while driving. Reverse the car, if the car jumps out of gear while doing so, the gearbox is badly worn out.
10) If you decide to buy the car, check the car's HPI record. You can find out if any money is owed on the car or if the car has been written off or stolen.