Answer:
Neither bought nor sold but more valuable than gold. It is built but not by hand. What is it?
I have many feathers to help me fly. I have a body and head, but I'm not alive. It is your strength which determines how far I go. You can hold me in your hand, but I'm never thrown.
This only turns over once you have traveled very far. What is it?
I tremble at each breath of air, and yet can heaviest burdens bear.
A house of wood in a hidden place. Built without nails or glue. High above the earthen ground It holds pale gems of blue.
You use it between your head and your toes, the more it works the thinner it grows.