Answer:
I am often sold by children entrepreneurs in summer time
I hatch without food
I make things short but I am pretty long myself
I am gentle enough to soothe your skin, light enough to fly in the sky, strong enough to crack rocks. What am I?
Everyone has me, but nobody can lose me. What am I?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.