Not long ago (historically speaking) one could get a cuppa joe for one thin dime. Not great, but usually drinkable. So with inflation the equivalent would be a quarter. A basic affordable cup of coffee could have a significant market.
~$5 for a cheap rolly bag, those usually last me about 2 weeks at ~3 cups per day. Even if my estimates are terribly wrong, we're talking a couple cents difference.
If your problem is with coffee you buy at a shop, then I think the issue is that you're paying for the wages of the person making the coffee too, and those have certainly gone up more than the rate of inflation since coffee was a dime.