By no means are my teaching partner (@Mr_Severino) and I the first to do this, and in fact there are many others who have posted on this topic, but I wanted to weigh in on what we have experienced in the past years. Topic: Physical Gold Currency in Classcraft and a Classcraft Economy.
What started as just a hands-on tool for money based Numeracy lessons, began to evolve into an entire entity over just a few months. Our first major move was to open the Shop of Classcraft where once a week students could buy small snacks and treats (both healthy options and sweets of course). But we slowly realized that a) not every student was actively participating in the extra optional quests and therefore were not earning money to even use in the store, and b) the ones who did earn were quite happy to blow their money of the stuff they liked.
So then started the Rent. 80 CC credits per week on Friday, somewhat offset by a small "earning wage", and now students were having to make the choice between snacks and actually having a desk . . . because (in fun, and only for a half-day) students who had failed to pay rent three weeks in a row had their desk reclaimed by the Gamemaster. Thankfully only three "evictions" happened last year, and students quickly got the message.
This is when the Economy started taking on a life of its own. Once we told students they could BUY their desk (and not have to pay rent anymore), some asked if they could buy OTHERS peoples desks as well, and charge them less rent than what I was asking for. I could not refuse. It was too awesome. And while this may sound a little too capitalistic for the Grade 7 . . . it actually took on an interesting altruistic turn when a group of students bought the desk of a friend who had been away due to family health problems . . . and wanted to surprise her when she got back. I was beyond impressed.
Financial Literacy is JUST as important as any other life skill students pick up in their early life. If we can offer them a perspective that would make them more prepared to manage their own finances in the future, then I think we as educators have a duty to offer such an experience.
If anyone is curious about the details of our CC Economy, wants the templates for our bills, or have any other questions, please don't hesitate to email me at firstname.lastname@example.org, or reach out to Frank and I on Twitter at @Mr_Severino or @PMarin1867