Research the market place
If you are interested in a particular model, compare prices from different advertisements. Check that you can afford the running costs such as maintenance and insurance premiums before you buy your dream machine.
Check that the seller actually owns the car
Check all documentation - V5, service and insurance records, MoT certificate
and receipts where available to ensure everything tallies. If the seller cannot provide the V5 walk away. There are plenty more similar cars on the market.
View the car in good conditions
Make sure you view the car in good daylight and don't go alone - take a friend with you. It is also important that you visit the car at the seller's house and do not arrange to meet at a service station or lay-by.
Find out if the car is on finance
Ask the seller if the car is on outstanding finance and check this out by making a Car Check. If the finance has not been paid off, the car could still be the property of the finance house who could reclaim it.
Check out the car
Make sure you get the vehicle independently inspected with an organisation such as the RAC. It could save you from a costly mistake.
Check the car hasn't been clocked
Turning back the mileage on a vehicle is a common trick to obtain a higher price. Bearing in mind the average car does 10,000 to 12,000 miles per year, is the mileage consistent with the age and condition of the car?
Check the car isn't a ringer
Ringing is stealing a car and changing its identity using the documents of an identical make and model. Check the VIN thoroughly and make sure it hasn't been tampered with. The VIN can be found in a number of areas on the car, including on the chassis, under the bonnet, on the floor under the driver's seat or etched on the windows.
Test drive the car
Make sure that you test drive the car on a range of roads for a drive of at least 10-15 miles. Make sure you are properly insured and take a friend with you.
Look at the car's history
Obtain as much information as possible from the seller, but realise that their objective is to sell you the car. Don't hand over any money until you have done an HPI Check - this will provide you with the vehicle's true history.