I was in the military and my Grandmother always sent me her homemade cookies. She would roll out the sugar cookies and cut them with the empty, clean Campbell soup can (or any brand). When the cookies were baked and cooled, they shrunk just enough to stack inside the empty soup can. This was a great treat to get several cans of cookies, uncrushed and wrapped up in wax paper. These make great gifts. Also a good Scout project.
Tuna and Vienna Sausage cans are pretty durable. I make emergency candles and camping candles or fire starters with them. I get some corrugated cardboard from any old box. I measure the depth of the can and then subtract about 1/4 of an inch. It doesn't need to be perfect, just below the rim. I use the premade wicks from the store, but wick cord cut to length works great. I roll the strips of cardboard and stuff it in the empty can. So it looks like a cinnamon roll. I melt paraffin or wax, used to seal jelly jars or use candle wax from the craft department. Poke the wick from the base through the center of the cardboard roll. CAREFULLY pour the melted wax into the can. How I melt the wax is I take a used metal coffee can, or something like that, those huge cans that family size or picnic size canned beans come in? After it is cleaned out, careful of the edges, I put the wax in that, then THAT can sits in a large pot of water and water is heated to melt the wax. No need to clean out the can after you pour the candles, once it has cooled down it can stored to reuse another batch of wax.
I use a locking wrench on the can of wax AND oven mittens to keep from the burning myself. I do this pouring on the patio so if I spill it, it won't mess up the kitchen floor. I leave them to cool over night and then package them in my emergency kit. They burn well, they are not for show, just emergencies. If I have to start a camp fire, these help keep the kindling burning so wet logs catch.
Be safe and tell me your ideas on how to prepare in a frugal way.