Answer:
I am bought by the yard but worn by the foot. What am I?
I can go through glass without breaking it. What am I?
When I am caught I am thrown away. When I escape you itch all day.
When I am alive, people sing. When I am dead, people clap hands. What am I?
I am all around yet to me you are half blind. Sunlight makes me invisible and difficult to find.
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.