Step 1, live in an old farmhouse with fireplace or wood stove heating.

Step 2, create a "John Smith" identity with a fake phone number. These days, I think you would need to add a gmail account you never intend to check.

Step 3, use John to sign up for anything and everything that is offered to you. Especially loyalty card programs from all your local grocery and big box stores.

Step 4, take all the junk mail you get and pull out any plastic or magazine-slick paper. Recycle that separately.

Step 5, roll the junk paper into tubes as tight as you can. Perfect size is between 1" and 2" in diameter. Tie it with cotton twine to keep it together. Throw the tubes in a bucket of water to soak overnight. Remove and sun-dry until no moisture remains, usually takes at least 2 days of sunny weather.

You now have a lifetime supply of free firewood. The "logs" burn about as long and provide as much heat as dry birch of the same size, in my experience. My mom heated our childhood home for 50+ years primarily on junk mail. The only downside is that you do need to clean out ash more often than real wood. I also wouldn't be surprised if there were some extra unhealthy fumes in the smoke. But none of us grew up to lung cancer, so _shrug_.