As I explained to my teenage daughter many years ago, the dealer may not make the profit they want; but they will not sell at a loss.
The NADA price is a good start point. Beware of prep, closing and other costs that seen to accrue.
If you tell them right off the bat that you are talking the number that you are going to write on the check including taxes it cuts though a lot of BS.
Also, I rarely by the same day I look. I like to sleep on it.
Good luck
Twenty six foot 2010 Dutchmen Lite pulled with a 2011 EcoBoost F-150 4x4.
Just right for Grandpa, Grandma and the dog.