Do your research
If you know what price you should expect to pay you'll stand less chance of being ripped off. Search big car sales sites like Auto Trader to make sure you’re paying the best price. You should also check sites like Parkers and What Car?, and national car dealers, to ensure that you know exactly how much a used car is likely to cost you.
Get the right car for you!
Whether a petrol or diesel car is more cost effective depends on how far you drive. The cost of diesel per mile is lower than petrol, but the price of a diesel car is higher. Find out how far you need to drive to break even using this cost calculator.
It also helps if you factor in depreciation, as diesel cars tend not to depreciate at the same rate, and can also be cheaper to insure.