Answer:
I cost no money to use, or conscious effort to take part of. And as far as you can see, there is nothing to me. But without me, you are dead.
You heart it speak, for it has a hard tongue. But it cannot breathe, for it has not a lung.
In your fire you hear me scream, creaking and whining, yet I am dead before you lay me in your hearth.
This only turns over once you have travelled very far. What is it?
What is it that no man ever yet did see, which never was, but always is to be?
If itโs information you seek, come and see me. If itโs pairs of letters you need, I have consecutively three. What am I?