I used Beanie Babies as an example with my kids. They wanted the "Princess" toy after Diana died, and I told them they were too expensive - "watch what prices do." Of course, the Princess came down hundreds of dollars, and ordinary Beanie Babies were being offered at sports card shows for a dollar apiece. As the kids watched the prices drop, their enthusiasm drained away.

It also enabled me to talk to my son about what "money" is from an economic point of view and the risks with Bitcoin. We have also discussed gold and silver (if the dollar really becomes worthless, and you use a one-ounce silver coin to buy bread, will the baker be able to make change? Is there an assurance that private label silver is really silver?)