Play through the history of money.
Start with barter, feel why trade gets messy, then discover how commodity money makes markets easier. The practical activity is Moneyopoly: Barter Market.
Barter friction
Players learn why direct exchange is hard when both sides need to want what the other has.
Commodity money
Shells enter as a common trading good, showing why some goods become easier to price and exchange.
Bitcoin bridge
The lesson tees up the deeper question: what makes money durable, scarce, portable, and verifiable?