>>Format it as $$,$$9.99. This will force the display of the 3 'positions' shown with '9' as numeric characters - 0 if there is no value in that position. The '$' symbol say to put the dollar sign directly to the left of the right-most non-zero number.

BTW. If you enjoy totally obstruse solutions, here's one I found that also works.

To print out x as a currency value with two decimal digits and a floating "$"

"$" + str(x,int(log10(x))+4,2)

Enjoy!