Answer:
When you buy me I am costly, but the only use I have is hanging only. What am I?
I am heavy forward, but backward I'm not. What am I?
I am quick when I'm thin. I am slow when I'm fat. Wind is my worst nightmare. What am I?
What is harder to catch the faster you run?
What is at the end of a rainbow?
When is it bad luck to see a black cat?