For your specific requirement,Cognito Forms is the best solution for you. It allows users to accept payments on forms. It is as simple as logging into Cognito Forms and selecting the existing form on which you want to accept payments. You may assign prices and calculate charges from a drop-down menu, radio-buttons or check-boxes.
If you want to charge users based on what they choose on this choice field, check the box for Collect Payments for This Field. This will automatically select the Assign Prices field and prompt to connect to your PayPal or Stripe account to accept payments.
After linking with PayPal or Stripe, you would need to assign a price to each option as these prices will be used to calculate the charges based on what your users select. Please note that if you leave these fields blank, they will be assigned a price of $0.00 automatically.
You can also select Assign Prices only if you would just like to assign prices to each choice, and these prices can then be used in a separate calculated price, such as for quantities. Cognito Forms have payment integrations with Paypal and Stripe for easy and secure payment.