Appraising Loot

Dave had mentioned a method of keeping track of secret loot values in a three-ring binder so that loot cards shuffled into the deck could be cross-referenced with a sales value. However, since there isn't any *appraise* skill of its own I'm not quite sure how to have PCs know the true cost of stuff. Since loot is the basis for XP, I thought this could be a very important bit of rules we want to agree on beforehand.

I've come across this post which has a few ideas that we might perhaps use. I specifically like this section:

As far as what skill can be used on this check, or whether a skill can be used at all, I leave it up to my players to suggest a skill that might apply and justify it. This puts the onus on them to decide what they want to use, and it has the additional benefit of sometimes letting them use something that wouldn't have occurred to me.

I like it because it occurs to me that PCs may have creative ways to appraise things that aren't clear. For example, one might use the Persuasion skill to just "make stuff up" about a particular item, essentially doing the exact same thing as a basic appraise roll.