remove Billing information and Payment method from the checkout page if there's nothing to be paid

Thanks so much to the maintainer jtsnow for this module.

Is there, in any way that I could remove the Billing information and Payment method from the checkout page if there's nothing to be paid?

And if it's possible, remove the Price info from the table as well.

I still need my UC to work as a shopping cart for other type of products with fixed price. So I just want the Billing information and Payment method to only appear if those type of products is selected in the list.

I hope that makes sense. Thank you in advanced.