Answer:
I am a little piece of paper, yet sometimes hold lots of value. I am all you need to get into big events, but will cost you. I am an important part of travel. And if lost, you're not coming. What am I?
I have a head and a tail but my eyes can never see my tail.
I am heavy forward, but backward I'm not. What am I?
I shrink smaller every time I take a bath. What am I?
I have branches but no fruit trunk or leaves. What am I?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.