Answer:
Travel a mile and I will change, travel a million and I will end as I started. What am I?
Of the king I am blue and of the peasant I am red. Of the frog I am cold and of the dog I am hot instead.
I am what no man ever yet did see, which never was, but always is to be. What am I?
My first is a heir; My second's a snare; my whole is the offspring of fancy; which I sent out of play upon Valentine's day As a token of love to my Nancy.
I can be sweet or sour. I do not rhyme with any other word
No matter how little or how much you use me, you change me every month.