I've done the Kroger thing... 4X fuel points on gift card purchases, plus I get the 5% "grocery" cash-back when using our AMEX Blue Cash card. I buy $250 in Amazon gift cards, get $1/gal off, plus I can use all 35 gallons if my Suburban is empty plus my 5-gallon gas can. It's good savings but a bit of a hassle. And the 4X thing only happens a few times per year usually around the holidays.
When traveling we use Google Maps and Android Auto for navigation. When we're running low on gas, I just say, "OK Google, I need gas." It immediately displays all upcoming gas stations with the price per gallon and distance to each. Very useful.
I used Gas Buddy when I was commuting. Back then, I filled up the Suburban every 4 work days, so it was worth it. Now that we are both retired, we don't consume enough gas to bother. I fill up about once a month, if that. Locally, we have one or two stations that we frequent, mainly because they are convenient (easy in/out), clean, well lit, pumps are fast, and usually good prices.