Warehouse find… the very desirable version made in wood. It is set up as a money box (US $). If you are skilled at crafts you could change for playing cards or billets.
Money Mystery Box: Place a small box down on the table. Borrow a dollar bill (or any paper money) from a spectator and have him sign it with a magic marker. Fold it up as you ask, “Is this the dollar bill you gave me?” When he confirms, say “Thanks!” and put it in your pocket.
Continue, “You can have your dollar back, or you can trade it for what’s inside the box.” Point to the box resting on the table. Whatever he chooses he’s in for a shock… Slowly reach over with your empty hand and bring the box over to the spectator. “Please remove the lid.” He does so and sees a folded bill inside. Dump it out and let him unfold it – it’s his signed bill!
A John Kennedy original that many prefer over the newer 3 D printed box.