Answer:
I go around in circles, but always straight ahead, never complain, no matter where I am led.
Long and thin red within with a nail at the end.
Tool of thief, toy of queen. Always used to be unseen. Sign of joy, sign of sorrow. Giving all likeness borrowed.
I have a gown but I'm not a priest; I have a crown but I'm not a king.
I have no wallet but I pay my way. I travel the world but in a corner I stay. What am I?
No matter how little or how much you use me, you change me every month.