Particularly interested in non-USA comments. Here in CO, there is gas pricing by oil company stores is by economic zones. You can compare the price of 3 same brand stations, say Shell, all within 10 miles of each other. Midgrade will be $2.43 at one, $2.33 at another and $2.35 at another.

Is this a US variable, a state variable, or an international variable?
If this pricing of profit maximizing is being used, what is the normal range of variances? 10c, 15c, 20c?