Before we went EVs we did this kind of thing a lot with our local grocery store chain. Buying groceries and gift cards from these stores on American Express Blue Cash Preferred credit card (6% back in grocery purchases) would effectively net you 18% off (in gasoline and cash). During certain promotions it would jump to 22% off. This means that anything you bought from Amazon, Ebay, Apple, Southwest Airlines, Disney, Best Buy, Universal Studios, Dicks Sporting Goods, Khols, Chipotle (and the list goes on..) would be at least 18% off. We would never purposefully buy something we didn't need from these stores, but rather if we ever had a need, we'd make sure we used this avenue to buy it.

The gasoline program at the grocery store changed a about 5 years dropping the discount yield to 13% which still wasn't bad. However once we went EVs we had no use for gasoline and stopped bothering with it.