Adding Coupon Codes for PayPal Checkout Payments

Can you add a coupon code widget or condition to zero out payment form?

I have a summary table the provides the registrant payment to select one or several registrants to pay. 

If we allow for someone to register for free, we need to provide them a way to do that. 

Payment Form A

https://form.jotform.com/90707741336155

Your team has been excellent in getting me to this point! You all have been very helpful!

Hello again,

I see your form is set up to calculate total and pass it to payment field. In this case, coupon code should be also involved in calculations. Conditions should be of help, I see associated statement is disabled at the moment, is there a problem with it?