A trio of characters are stuck in the past (1691, Salem), without any supplies, except for the clothes they are wearing and the items they have in their pockets. They don’t have any food, and their clothes aren’t appropriate for the time period. But, luckily they stumble upon a merchant with everything they need.
They have no money though. What modern day items that people commonly carry around would be best for trading with the merchant?
It must be something that isn’t too advanced, ie no cell phones or calculators.
They can trade the clothes they're wearing as well.
They don’t care if the item gets found in the future, so that isn’t a problem.