i'll make you a great deal.  $6800 for this great car.
Hello. I am interested in purchasing this car. I have been looking and shopping around for cars for myself. But the prices have always held me back. 
this is an incredibly fair price for this car.  it is fully loaded.
I can't do 6800 its out of my budget. I am willing to spend 6300 on any car purchase as that's about what my budget allows me. Have you driver this car before? 
yes, it's been my car for years.  it's a great car.  i'm sorry to part with it.  $6750 is fair for both of us.
As I mentioned before the amount I can spend is 6300 max 6400 because I can't afford more than that, and since this car is old, I believe the price is still fair. 
i'm willing to compromise for you at $6600.  that's a steal of a deal for a car this good.
Okay, I will accept that amount, but I would want to come and see it and test it around as well please