Budget
The most important thing during the negotiations is staying objective. Do not let the salesman tempt you into making any rash decisions. If you have a car to trade-in, it is not always the dealership that gives the highest trade-in price, that is the best overall deal. It is better to make a budget and start the negotiations from what you want to pay extra.
For example:
You saved 10.000 pounds and have a car to trade-in. To set your total budget, you will have to determine the possible trade-in price for your car. You can do this by comparing similar cars to yours on the popular websites. Determine the trade-in price by subtracting about 1.500 pounds from the asking prices. Now you add this figure to your savings and you know approximately what you can spend during your search for the ideal car. After you have made a selection online, visit a couple of dealerships.
When you let several dealers value your car, the trade-in prices will differ, but the price and conditions under which the cars in stock are offered, will differ too. The dealer with the most favourable asking price, can easily give the lowest trade-in price. That is why you have to keep the big picture in mind, and not just the trade-in or asking prices.
You should also calculate the secondary advantages, such as longer and more extensive warranties. The more expensive car can give you extra warranty and road-side assistance, while the cheaper car has only the minimum amount of warranty and service.