If the coffee has been roasted and ground, it’s not worth trying to store for the long haul: it’s going to go rancid on you and become not only undrinkable but dangerous to your stomach. It doesn’t matter how well you seal it up: time is going to do it. Alas. It’s definitely the kind of thing one would miss out of all proportion once the habit is ingrained; it certainly is with me. If you can find them, you’d do better with unroasted coffee beans. Keep them cool and dark and only roast what you need for about a week.
I too, live on very little as a rule, for as a widow, I’m the only human I need to cook for, but as I don’t want various toxic molds living off of me, I’d draw the line with eating out of dumpsters – and so should you. Most bread products sit on their shelves encased in a plastic bag till their sell-by date expires, when they are tossed. You may not see any obviously moldy patches but that doesn’t mean that mold isn’t there: the breads are stored in exactly the right conditions for it to develop!
I’m coming to approve of you because I like the way you think on many topics so I don’t want you to come down ill. There are safer ways to do bread on the cheap and I know them all.
Buy a (non-electric) grain mill, a good set of grinding stones – the traditional Mexican metate is still one of the most practical kitchen tools you can own – whatever you can afford and start buying your grains whole for storage. Feed stores have sales too. Even those have a limit, of course. Hard winter wheat stores better than soft wheat, white rice stores better than brown, again because those oils turn rancid, blue corn stores better than yellow or white but you can still use all those in the short term, very cheaply.
You’ll get more for your money grinding your own grains and making your own breads – a task that can be done just about anywhere, so long as you have hands, water and a heat source. Do store some dried hops if you can; they’re cheap. A tea of that added to your batter will give you a starter in 24 hours to raise your batch of bread. For now, buy your dry yeast by the pound, it’ll last for years. Interestingly in most supermarkets, only the small expensive packets are in the ‘baking aisle’ but the pound bags are in the Mexican or ‘importeds’ section.:)
You can in turn dry out that homemade bread very thoroughly and store some of that. Never under-bake! That’s where most people screw up: you must kill all that yeast before trying to dry. Whenever I bake loaves of bread, I slice and dry one of them for zwieback. Kept completely dry, it’ll last a long time. You can eat zwieback even if you can’t stomach anything else, it’s very soothing to the belly. If you don’t have an oven you can still bake bread on a iron skillet with a lid, preheated at least 15 minutes to get even heat, then turned very low – till you can turn that bread to cook on the other side with just your fingers.
Once you get the hang of producing your own breads, from plain tortillas and flat breads to raised loaves, even with a few hilarious mistakes along the way, and runs of plain bad luck, I promise you that nothing else can be quite as satisfying to you. You can eat out at the best professional bakeries, but your teeth will still miss your own bread. It’s hard to explain.:)