Answer:
When you buy me I am costly, but the only use I have is hanging only. What am I?
I am a piece of paper that takes most people 3 or 4 years to get. What am I?
I am the tool for inspiring many. Buy me in the store for not much more than a penny. Don't overuse me, or my usefulness will go. What am I?
I am a king who's good at measuring stuff. What am I?
I am the outstretched fingers that seize and hold the wind. Wisdom flows from me in other hands. Upon me are sweet dreams dreamt my merest touch brings laughter.
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.