Value it should have been?
I agree this was poor wording on my part. Replace it with "the subjective value from the perspective of the seller".
How can you shift fault to the buyer for wanting to score a good deal?
I did not assign fault, nor am I interested in doing so. My point was related to the one-sided questioning of ethics. Hey, one may very well stumble into a thread where somebody is selling a $400 knife for $10; and one would be perfectly aligned with forum rules in obtaining that knife for a sawbuck ("for a steal", as you said). But is it ethical to do so? I'm not confident everyone would agree on the answer to this question.