Digital assets and currencies
Understand assets, networks and trading mechanics with sources you can check.
Tuzex was a series of state-run shops in Czechoslovakia from 1957 to 1992 which did not accept normal Czechoslovak koruna currency but only vouchers (bony) which could be purchased from banks using foreign currency. They supplied luxury items: local goods in short supply and in particular foreign goods. The Tuzex vouchers were effectively an unofficial parallel currency.