A couple of weeks ago I was visiting Fort McMurray and discovered a 22 cent per liter price difference for diesel, between the Shell retail station (near entrance to Beacon Hill I think???) and the Fly J card lock just 2 blocks or so south, on the west side of Hwy 63. I was able to pay with a credit card as my card lock provider wasn't valid there. I didn't check gasoline prices so not sure if the same differential applies to it or not. As I was only in town for a week I couldn't tell whether or not this is ongoing or just an isolated anomaly but figure I saved over $25/tank by filling up there. I will certainly be checking again when I return!