Back to a barter system, plus in earlier times when actual money was in short supply stores introduced their own trading tokens, and even if the banks will not deal in cash anymore the notes have printed value so they can be used to barter
Through the ages there have been many items that have been used as currency, this will continue IMHO as we all have to adapt and continue living in spite of governments
Also ultimately we are many they are few, and also they (government) do not serve any useful service anyway
