Are we not at risk on conflating price and value here? The price set by the seller presumably reflects their perception of the item value, but the value the buyer places upon the item will dictate ultimately what they are prepared to pay for it.
Whilst the seller must surely be free to price items as they see fit, in these days, as others have said, price research is not exactly difficult so there must also be an element of caveat emptor.
YMMV of course.