3. The kinds of money Personal possession of currency is prohibited in Canadian prisons; although, in practice, prisoners still exchange goods and services. Until 2008, the year in which the Canadian government banned smoking in federal penitentiaries, cigarettes were the preferred medium of exchange among prisoners. One important difference between using cigarettes and using dollars as money is that have intrinsic value. Cigarettes are an example of money. Grade It Now Save & Continue Continue without saving