Start by finding the “Blue Book Price” from this website (kbb.com) or another similar pricing guide. This is the Kelly Blue Book website and it allows you to find a standard price for your used car based on the year, model, condition, features, etc. Use this book value as a starting point. If your car is special or in high demand, maybe you could ask for more. If there are a lot of similar cars for sale in your area, consider asking less.