Here in NW Buckeyeland, it's Currently down to $2.04 USD($2.73CAD)/US Gallon (70.91 Cents/L)
Last Summer I drove my Mom to one of her High School Friends' house in Guelph, ON. (333mi one way) I did my gas research beforehand, and made sure i would have enough to get back to the states.
I made it from my house through the Tunnel to her House, and back to the US Side of the Blue Water Bridge at Sarnia/Port Huron on one tank. granted, i was sitting in the US Customs line "on fumes", but, i made it. Hit the First Station I saw in Mi, when i went to reset the trip odometer, it was at something like 499 mi.
when i went back 10 days later to get her, I made sure to top off about half way to Detroit.