Answer:
I drive men mad for love of me. Easily beaten, never free.
I can travel from there to here by disappearing, and here to there by reappearing.
To unravel me you need a simple key, no key that was made by locksmith's hand. But a key that only I will understand.
I am the tool, for inspiring many. Buy me in the store, for not much more than a penny. Don't overuse me, or my usefulness will go.
Runs smoother than any rhyme, loves to fall but cannot climb.
Iām grown from darkness but shine with a pale light. Very round I am and always a lady's delight.