My mom would use Super America or a gas station that is close to my home (privately business owned, used to be under Marathon/Tom Thumb), and on road, it depends if we see one. Minnesota used to have 7-11 back in 80's but not anymore, I guess Super America beat 7-11. When I visited Texas last March, I seen lots of 7-11 down there besides Shell and shramock (? if I am right?). Minnesota does have Shell, I saw one recently, I forget where. MN also have Holiday, Tom Thumb/Marathon, Phillips 76, Amoco (now BP), Rainbow Food gas station (cojoined with the grocery store), rare Wal Mart, Casey's, Sinclair, and Conco. If I think of anymore, or see one, I'll post more...
Fleet Farm too...