Most new car buyers have a used car they need to get rid of. You generally have two options - you can either trade it in at a dealer, or sell it yourself to a private party. I recommend selling to a private party if you want to maximize savings. Yes, there are some hassles, but it's usually worth the extra savings.
Dealerships make more money selling used cars than they do new cars. Just look at the difference between retail and wholesale prices in any popular pricing guide and you'll see it's huge. Consumers are so caught up with "haggling" over the new car price, they get blindsided by the trade-in. It's amazing how many people consider the trade-in an afterthought, leaving thousands of dollars on the table.
If you're thinking about trading-in, you need to seperate that transaction from the purchase of the new car. If you combine them, the dealer has a lot of room to play around with the numbers. They may offer a good deal on your trade-in, but rip you off on the new car, or vice-versa. Bottom line: You still end up with a bad deal.
Despite my warning, if you still insist on trading-in your old car at a dealership, you should complete the following steps to get the most money in your pocket.
Knowing this, you will use these pricing guides only as a ballpark figure. Factor in a possible range of plus or minus 25% for whatever the pricing guides state. For example, if the guide says your car is worth $10,000, the ballpark range is really $7,500 to $12,500.
But not just any dealership. Make sure to go to a dealership selling the same nameplate as your car. So if you're wanting to sell a Toyota, contact Toyota dealerships. This is important because they'll generally offer you a better price than an unrelated dealer. This is because people tend to shop by nameplate. Someone going into a Toyota dealership is more likely to buy a used Toyota rather than a different nameplate. The dealer can offer you a better price because they'll be selling your car on their used lot instead of having to sell it for wholesale to another dealer.
To get offers, first call nearby dealerships and ask to speak to the person who buys used cars. Tell them the year, make and model you're selling and let them know the car has been well maintained. Ask if they would be interested in seeing it. If not, you've saved yourself a time-consuming trip. If yes, tell them you'll be over there within a couple of hours. Repeat this process until you have 3 dealerships interested in seeing the car. Unfortunately, if you live somewhere that doesn't have many dealerships, try calling dealerships that compete closely with your nameplate (example: Toyota and Honda). You won't get as good a deal, but it's still worth getting offers, and don't forget about used car superstores such as CarMax - they're always interested in purchasing used cars.
When you get to the dealership, ask to see the person you spoke with. They will take a look at your car and come back with a price (usually a low-ball offer). No matter what price they quote, tell them the offer seems low compared to what you've been quoted elsewhere. They will either say that's the final offer or will ask what price you've been offered elsewhere.
Whatever price they first quote, come back with a price about 15% higher. So if they quote you $10,000, say that you believe the car is worth at least $1,500 more. Wait for their response. If they say "no way", ask if that means the first offer was their best offer. If they say "that's too high", ask them how much higher. Chances are, they will offer you a higher price.
You're not done yet. Tell them the car is in great shape and won't result in any problems. Counter with a price halfway between their last offer and your original counter-offer. Say you think the car should be worth that much and see how they respond. Either way, when you're done, you will have a good idea as to what your car is really worth. Repeat this process until you get offers from 3 different dealerships.
If your car is over 5 years old or has over 75,000 miles, chances are a new car dealer will not put that car for sale on their lot. Instead, they'll just sell it at wholesale price either to an independent used car dealer or at an auction. So if you trade in your car, the dealer will just act as a middleman and pocket some profit at your expense. In this case, you should shop your car to used car dealers directly. Go through the same process above - just with independent used car dealers.
Most dealers will ask if you want to trade-in. They're hoping you're a sucker who won't realize they're making a killing off your used car. During the car buying process, you can say you have a trade-in, but that you want to negotiate the price of the new car first. After you have done so, you can see if they can beat the prices you've gotten from other dealers.
If they can beat it, great! If not, that doesn't mean you should stop there. First, find out beforehand if your state offers tax advantages for trade-ins. If so, you're allowed to deduct your trade-in value from the purchase price of the new vehicle. If your new car costs $25,000 and your trade-in is worth $10,000, you pay taxes only on $15,000. If your state charges a tax of 7%, that's a $700 savings. So make sure you take that into account. In the example above, if the dealer you're purchasing from offers you anything above $9,300 and the best offer you got elsewhere was $10,000, you would still save more by selling to the dealer.