Having been a long time border resident we have dealt with exchange issues many times over the years. The best exchange rates are the banks. That take some pre planning. Next if you can find a credit card without charging int'l fee that post exchange rate given on the day of purchase. Even currency exchanges charge a 'fee' in addition to the rate. That fee is probably the highest at the ones nearest the border and tourist places. Then grocery stores on the U.S. side and beer stores on the canadian side.