Kroger has a fuel rewards program that lets you earn fuel points on grocery. The wonderful part about it is you can use the savings at Kroger fuel or Shell (Top tier) for a few cents off/gallon.
You could also get 4x fuel points on friday, so a $100 grocery run on Friday gets you 40 cents off/ gallon. Helps me save around $15 a month on average. There's probably other chains doing the same, so if you shop regularly at one of these places, just check up on their rewards program and partnerships.
EDIT : They make you clip a coupon on their app EVERY WEEK to earn the 4x points on grocery. You still get 1x points on grocery otherwise without the coupon.