One of the area grocery stores gives you $0.10 off a gallon at Shell for every $100 you spend there. It's a one time savings, but depending on how much you spend, it can add up pretty quick.
While not shell, citgo also offers free gas through their good rewards program with visa. Register your visa credit or debit card, and for every 8 times you put in $20 or more, they send you a $15 gas card. If you usually put in $45, you can put in $22 twice and it counts as two visits.
www.citgogoodrewards.com