Answer:
What is black when you buy it red when you use it and gray when you throw it away?
I always follow you around, everywhere you go at night. I look very bright to people, but I can make the sun dark. What am I?
They come at night without being called and are lost in the day without being stolen. What are they?
I only exist when you are here. Where you never were I can never be.
What can you catch but not throw?
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.