In my business, I am constantly buying and re-selling goods. I have also bought quite a few vehicles over the course of my life. And yet I still don't get why some people include what they pay for sales tax and labor/delivery/installation as part of the value of their items. Those are incurred costs you have to pay, but in no way add any value on their own. And they use these things to jack up the price they want to get. Whenever I come across someone trying to get back a portion of their sales tax and labor costs, I just walk away. Because I know at that point I am dealing with someone who over values what they have because of their sentimental attachment to it