Oh! Look at this. A shining plate from tiamat. Shopkeeper tells you: 'Yeh, hand it to me and you get this nice potion worth 100 copper.'

The current barter seriously hamper outlander. They are dependant on barter. It WOULD make sense that the shopkeeper atleast gave you some worth back. Look at this real life:

You walk into a store where they sell clothes. Gives the key to your porche to the shopkeeper and ask him what you get in return. He offer you a pair of pants and you accept.