I have a scale that's also enchanted, it's a bit big, but the magic on it allows me to gauge 2 different things in terms of value. Sometimes I trade favors instead of items. Write the favor on the piece of paper, and it's measured in value against the value of the item. It's also mostly how I get bits. I trade something they need for a different object they have, and I sell that sometimes. Usually those don't have magic on them.

Uh huh…

Well, whatever works, I guess!