Heh, at least he's not trying to sell a Hummer.
No pun intended.
I think most people don't even know about book values. I think most don't know that if you find out the base value of a car then you can go to a dealership and work from the book price up, instead of the dealership price down, and sometimes even get it for the book price.
As for buying from individuals... different principle. Here it's a game of who's more determined, or who can bluff better.
...I don't like games, but... I also don't like spending (or losing) money.