You could try autotrader but you will want to make sure you are being realistic with the price as it is quite expensive. Other sites you might want to try are eBay motors, webuyanycar (car buying company) and quicksellcar.co.uk (car selling comparison website).
I think the best place to sell a car on the web is OLX
One of the best websites to sell a car that you own, is on Craiglist.
Craig's List.
"The best place to purchase a Chevrolet Silverado 3500 is anywhere that will sell it. The best place, of course, to buy a car, is from the dealership place."
Your best bet is to place an ad and sell the car. That, or sell it back to the dealership.
There are a plethora of dealerships that sell new cars. Shop around for the best deals. Check your local newspaper for the latest car sales and specials.
You should look into trading your car to a nice used car dealership. A good used car dealership will take what your old car is worth and put it towards your new car.
The best place to sell a 2007 Chevy in Tahoe would be online or in various car trader magazines. If you really want to sell your Chevy, you have to make it known that you want to sell it. How many newspapers are there in your town? Advertise with them. You might have to spend a few dollars, but it's worth it.
In the back row of your car is the best place.
eBay is a good place to sell cards.
Where is the best place to sell a quartz watch at for good deal
the best way is to sell it in a car show like mecum auto auctions