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?

 Hi John,

This can be done with a feature we call EnablePGateway.  Check out our Form Demos and see Demo 17.  This example was built with Dynamic Forms and for PayPal but it should work the same way for Dynamic Registration and Authorize.net.  The key is to use EnablePGateway as the short field name for the field that triggers the free or paid subscription.  Thanks and please let us know if you have other questions.

Candace