I have created a page with a custom form that prompts the user to select a series of radio buttons based on what services they need. Each button that they select is associated with a cost. I am totaling the cost of their selections inside the page code, and I am able to display this total at the bottom of the page in the form of a text string. From here, I need the customer to be able to click the submit button and be directed to a payment form or payment page with the previously calculated total automatically filled in for the amount to be charged. I have seen several "payment button" options but these options either only allow for a fixed amount to be charged or for the user to select the payment amount his or herself. Again, I need for the user to be prompted to pay the total that has been calculated based on what they have selected. Any suggestions on how to implement this?