Rocket stoves are so simple to make that it is easy to make them from whatever you have handy. This, of course, is dependent on you understanding what makes them work. It is a fine example of a favorite saying I made up: "The more you have in your head the less you have to carry in your hands."
Some survivalists can walk naked into the woods and come out fatter with clothes on. Other, less knowledgeable people, can starve to death right next to food they don't recognize.
If you are capable of it, learning the theory of rocket stoves will mean you can be safe and warm without having to haul around an actual stove. Learning what makes rocket stoves work means that you can make one out of whatever you have handy. That is a lot of freedom and security for you and your loved ones.
It is no shame if you cannot learn the theory of rocket stoves. If not, then you will just have to buy or make one and make sure you can get it when you need it.
Link to research center that invented rocket stoves
The Aprovecho Research Center provides technologies for poor people in developing nations worldwide. Their rocket stoves are only part of their efforts.
This guy used a hole in the ground with a bit of pipe for a rocket stove for camping.
I ran across a blog where a guy used nothing but a hole in the ground and rocks to make a rocket stove. I have not found it in time to add to this post, but will provide a link to it as soon as I do.
I would like for all my readers to have the freedom and security of knowing they can always manage to have warmth and ability to cook, no matter what arises.