When the price of your new car, the value of your trade-in and the loan terms are all discussed at once, it's hard to tell where you're getting a good deal and where you're not. A generous trade-in offer could be balanced by a higher price on the new vehicle, or the other way around.

Research what your current car is worth before you visit any dealer. Online valuation tools can give you a range, and some dealerships and car-buying services will give you a written offer for your vehicle whether or not you buy from them. Getting a few offers shows you what the market will pay.

At the dealership, negotiate the purchase price first. Once that's settled in writing, bring up the trade-in and compare the dealer's offer with the others you've gathered. Selling privately may bring more money, though it takes more time and effort, including handling showings and paperwork. In some states, trading in can reduce the sales tax you owe on the new car, so weigh that too.