Hide credit card panel if no chargeable items selected.

I have a form which allows users to order both free and chargeable items. If only free items are ordered, I would like to hide the request for credit card data.

As per checking, you are using a payment field to list out the products. Unfortunately, since this is just one field, it is not possible to hide one section and show the other.

If you want the payment field to be conditionally hidden, you can list out your products using regular fields, assign calculation values and use Form Calculation widget to calculate the total, then pass that total to the payment field. 

How-to-Assign-Calculation-Value

How-to-Perform-Form-Calculation-Using-a-Widget

How-to-Pass-a-Calculation-to-a-Payment-Field

You can then add a condition, that if the total is zero, then hide the payment field.

How-to-Show-or-Hide-Fields-Base-on-User-s-Answer