How to get the best deal on 12-pack sodas?

I am trying to stock up a relative's small fridge with as many drinks as I can fit in it (luckily it's a smaller fridge ~7.5 cu ft.) but drinks are SO expensive right now. Their go-to favorite is Dr. Pepper at the moment. It's looking like Dollar General might be the best option but I'm terrible at finding the good deals and want to see if anyone knows of anywhere cheaper atm. Thanks!