Using Caldera Forms. I have set up most of fields forms. I want to add a payment gateway that responds to the currency rates that the user input. Also it will request the user to input name and email according to the number of people they input. And using the emails collected, I will send them a questionnaire once they paid.
Read to start now, will provide you custom solution for your payment gateway integration for your already created forms, Will serve exactly like your wrote. Looking forward to hear back from you...