I remember when I was a kid in the late 40s and early 50s we would visit my father's home town of Rouses Point, N.Y. just across the border from Quebec. You could just walk down the street into Canada with no customs. It was like one big country except for the money. The exchange rate was usually 1 to 1 but every so often one of the currencies would be a penny or two more than the other and the one of lesser value would not be accepted in the country where their penny was worth more. You had to go to a bank and change your money. I guess back the a penny was really worth a penny.