The appraise skill and the ID spell are, like every other skill and spell in
the MUD, not 100% flawlessly perfect. Using them to get the general value of
an item is not a bad idea, but using it to claim the item's value down to the
mowgle is just not that smart. If you are doing a merchant quest based on
value, therefore, it might not be a bad idea to ask for a second opinion
before you sacrifice something you can't get back.