Answer:
I always have to work with something in my eye.
I cannot be bought, cannot be sold, even if I'm sometimes made of gold. What am I?
I am one small little piece of paper yet sometimes hold lots of value. I am all you need to get in to big events but will cost you. I am an important part of travel. And if lost you're not coming.
What goes up a chimney down but can't go down a chimney up?
They come at night without being called and are lost in the day without being stolen. What are they?
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?