Russ Roberts over at Cafe Hayek has an interesting econ puzzle:
An American tourist goes to a remote island for a vacation. The natives live by a barter system-they have no money. When the tourist tries to pay for his lodging with a check, the owner laughs at first, but then decides that the design on the check is quite attractive and agrees to accept the check in return for lodging. This happens again when the tourist pays for food and some native artwork. The checks are never cashed. They begin to circulate on the island as money, replacing the barter system that had existed before.
If the checks are never cashed, who pays for the vacation of the tourist? Or is it free?
Think about it for awhile. I'll be back later this evening to post my thoughts on it.