The core of it is free banking: anyone who wants to can produce their own currency and manage it however they want. The exchange rate to the standard monopoly c

The core of it is free banking: anyone who wants to can produce their own currency and manage it however they want. The exchange rate to the standard monopoly currency is determined by the market. Another major element (though more common in house rules) is that arbitrary agreements between players are allowed, enforced only by one's honour. (These rules probably only work when sort of the same group of people play multiple sessions.)