Now you're starting to piss me off. Why are you complicating this unnecessarily?
Geez robert, what if they have a 20% off sale? What if the customer returns the product? What if it's damaged? What about a shoplifter -- isn't he really paying the hidden tax?
If the company doesn't sell the product they go out of business -- which is what will happen when we have the Fair Tax and everyone starts buying used products instead of this guy's new stuff.
"Are the buyers paying tax or reimbursing seller's costs?"
Who ... cares ... what ... you ....call ... it? Think of a service industry -- a lawyer, for example. The hourly rate he charges you includes the taxes he has to pay the government. If he didn't pay taxes he could charge you less.
This is why the illegal immigrant is so cheap. He doesn't pay income taxes. If he did, he'd charge you more to cut the grass. Meaning ... YOU are paying his income taxes when you hire him!
With the Fair Tax, your hated recreational and black-market prescription drug dealers would have to pay their fair share of taxes.
What gives?