This question appeared in the New York Times Magazine: Is it ethical to buy something at a yard sale or a flea market at the seller's asking price if you know the value of the item to be significantly higher than what is being asked? Let's say, for example, someone is selling an old comic book worth thousands of dollars but asks for only a quarter because he or she does not know the true value. Is it incumbent on the seller to do his or her research? If the seller does not, is it fair game? Does the buyer have any obligation to inform the seller?