An Old-Fashioned Girl Scout "Buddy Burner"
My favorite home-made camp stove is a bright, if distant, memory. Way back in the last century, when I was a Girl Scout, we used to make our own "Buddy Burner" camp stoves for camp-outs or a burger cook-out at the beach.
It was simple enough for... well... a child to make (with a little explanation).
1. Take a clean large can, like a big coffee can and make a few triangular vent holes around the top edge with a can opener. Set aside.
2. Take a tuna or small cat food can and wash it well.
3. Cut up some strips of cardboard the same width as the height of the small can. Beginning at one end of the strip, coil it until you have a coil that completely fills the tuna can. Insert it.
4. Light a paraffin candle or carefully melt some chunks of paraffin like you buy in the canning supplies at the supermarket. Let the burning candle drip paraffin down into the cardboard or (easiest) pour the melted paraffin over the cardboard until it is completely saturated.
You now have all the elements. To use the stove, light the paraffin-soaked cardboard in the tuna can and get it burning well. Set the large can over it flat side up. The top of the large can soon will get quite hot. Plunk your hamburger patty (or whatever) on the can top and cook it (while your potato is baking in tinfoil in the coals of the campfire).
I do have to admit it has been more than 50 years since I actually did this, but the memory sparkles. I can't see why it wouldn't work as well today as it did then.