currency field that can be auto-added to total credit card amount

Hi,

You can use our Calculation Widget for that purpose. Here's how: http://www.jotform.com/help/275-How-to-pass-a-calculation-to-a-payment-field.

If you need to total all field value selection, you can also do it using our calculation widget. I see that you have Radio Button fields that is configured to have a pricing. You can then pass it to the Payment Field with a donation option.

Let us know if you need any further assistance.

Thank you!