I'm no expert, but to take the example originally posted of a Superb example of Scott 942 selling for $95 and then look at these two side-by-side:
http://www.bidstart.com/search_resu...itsearch=#idThe same seller, the same pricetag ($95) for a Superb 98 and a $60 reduction if you're willing to settle for a Superb 95 ($35)--and even at that it's overpriced.
I would venture to guess that most people couldn't see the difference between these stamps.
Also remember that these are all "asking" prices, no one has yet bid on the item(s) and the "buy it now" price is typically for someone who just can't live without it. Considering no bids have been recorded on either example, most people (myself included) can very comfortably live without the stamp at those prices.