My new go to Youtube mechanic is Scotty Kilmer! Here Scotty gives some advice on filling up. He recommends you NOT fill your gas tank until it can take no more, and why.
In the old days before paying for gas with a credit card became common, you would try to make the dollar amount come to the nearest dollar or fifty cents to save on loose change. But these days, I rarely pay for gas with cash, so following Scotty’s advice is much easier.