In a post-coin operated world, it is getting trickier and trickier to deal in cash. As we all know, transactions without cash have a cost, an actual fee for moving the virtual money around, and the costs we incur by being more oblivious about the actual amount of our money (or the bank's money) we're shifting around. However, I have also started to wonder how a cashless society is understood by my kids. Recently, we had a fun time playing with friends in a river that necessitated a trip to the laundromat to dry out our shoes. The coin slot happily took our money, even though it didn't always reciprocate by actually starting when we pressed the button. I couldn't help but think that it was rare moment of my kids observing and participating in a coin transaction. Their experience with payphones is limited and they have only occasionally seen me use one. My daughter asked me if I knew what penny candy was. She told me she was studying it in social studies. ...