Even dealers have a price of what they would want for their rig. Its the same concept as if you were selling the unit. What would you accept for the rig if you were selling. Do your research across the country and see what that particular unit is selling for, with the same options as close as possible. I just purchased my rig 3 months ago, and I had to do just that. Everybody has their price, and the dealer had his price. I presented him a price and we finally came to a meeting of the mind. 20 to 30% is a start depending on condition. Good luck