If you want to save money and possibly make money on your used vehicle, don't trade it into the car dealership!
The auto dealers are going to buy your car for wholesale, and then turn around and sell your car for a profit. It may be tempting when you have your eyes on a nice ride, and you are anxious to get rid of the car you have. Believe me, I have been where you are!
I was extremely tempted to sell my Volvo to a Ford Dealer who offered me a measly $3500 for the car. Well I owed about $6000 to my finance company which meant I would've been out of a couple thousand dollars...a nice down payment on a new car. Being the practical person that I am, I decided to take the advice my friends and put the car on www.Craigslist.com for free. My friend have had great experience selling her car on Craigslist. She told me that she sold her broken down Saturn that had issues in less than a week! She was upfront about the much needed repairs and someone bought it as is!
I decided I would put my car on Craigslist to see what would happen. It was in good condition, but in need of new tires. I sold it in about a week, and even though I sold it at a loss (to account for the needed tires), I was only out of pocket a few hundred bucks instead of a few thousand. If the car had some better tires, I would've been able to get at least what I owed on the car.
Save money and try to sell your car yourself. You don't even have to spend any money advertising it, I didn't! So now I'm free to lease or purchase a new car without rolling over any payments. What a great feeling!