What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
I am not sure if I have understood your question correctly. Do you mean to say that you want to display selection of your payment question at the bottom of your form?
Unfortunately we do not have built in feature but with a little workaround it is possible to achieve your requirement. You will have to add normal form fields to display your products. You can take advantage of our "Form Calculation" widget to calculate the price and then pass it on to your payment question. The following guide should help you on how to pass calculation value to payment question: https://www.jotform.com/help/275-How-to-pass-a-calculation-to-a-payment-field
Let me create a demo form for you and get back to you soon.