I have both free and paid subscriptions when a user registers for the site. I only want the credit card functionality to fire off when someone selects a paid subscription type from the drop down. When they select a paid subscription, a hidden credit card, exp date, etc... fields show up and I only want to do a transaction under that condition.
If they select a free subscription, they should be able to register without getting a "credit card required" error.
How can I handle this?