Answer :

TaylorBayley
I'd actually write is as $0.50, so clarify the fact is is zero dollars and fifty cents, in business especially you don't want people to miss the decimal which is quite possible if it isn't preceded by a 0.
You should write it like this:

$0.50

I'd agree with Anthony. It is important to write 50 cents in this manner for business purposes. It's very precise and clear.