Be careful of Canadian tolls if taking car across border

Good pick up and drop off. No issues with car. Counter staff did try to sell upgrade but were polite enough. Should have taken up full to empty offer as finding pump and filling up at JFK was not that easy when rushing around. Fuel economy was very poor on car. Took car to Canada and even though paid for vehicle toll per day stuck with bill afterwards for Canadian toll. Should have been advised accordingly as asked twice about this at counter