How to create a payment form to collect a fixed amount from each respondent?

You can use the Peergateway addon to setup your google form and collect a fixed amount from your users.

Setup payments

Prerequisite: You must have installed the Peergateway add-on for Google Forms. If you haven't installed the add-on yet, you can install it from G Suite marketplace using this link.

Step 1: Open your form in Google Forms. Click on the addon icon and click Peergateway.
Step 2: Peergateway menu will be displayed. Click Configure payment.
Step 3: Configure payment setup wizard will be displayed. Select Paypal and click Next.
Step 4: Enter your paypal.me link, select the payment currency and click Next.
Step 5: Select Fixed Amount and click Next.

Configure payment amount

You can setup your form to collect a fixed amount, dynamically calculate the amount based on the answer or add custom formula to calculate the amount. In this example, we will setup the form to charge a fixed amount.

Step 6: Enter the amount that you would like to collect and click Next.
Step 7: Click Preview.