Whatever I am buying. If the initial asking price is not realistic I move on.
If the asking price is over what I think is a fair price, based on model, age and condition, then I assume the seller has built in a buffer so I offer a little under his price and see where it goes.
If the price is fair, I don't quibble and pay the asking price so I don't screw myself over a few dollars.
On average, I believe more problems start with the seller, than the buyer.