Yes, atVenu Register does work in Canada.
The numeric prices of your items in atVenu Register remain the same as in your Count page for the show. Your customers will be charged that price in their local currency. You can always change prices per item / per show to account for conversion rates on our Merch Mgmt packages: How do I change prices for individual shows? (Tour Merch Mgmt).
atVenu Register Credit Card deposits are converted to the currency of the saved Bank Account (USD or Canadian Dollars) upon transfer.