If you're selling a single item, such as a book, and the price is fixed for all users submitting the form, then setting up your form should only take a few minutes.
Start with a blank form and give it a Title. Next, add fields for Name, Email, Phone, Mailing Address and any other fields you need to collect from the end user to process each order. To add those default fields to your form, just drag and drop them over to your form from the form builder toolbox on the left in Build mode.
After that, we want to add a Number field to the Form to represent the price for each book order. In this example, we added a Number Field and titled it "Price Per Book". It's important to set this field to "Read-Only" so the end-users cannot edit or delete the total due.
Now that we have our form built, we need to add a third-party payment processor. They all work similarly, but PayPal is the most common one used, so for this example, we will use PayPal Website Payments Standard. To add the PayPal integration, go into the Form > Settings > Integration Hub > Payments > click the Add button next to PayPal.
With the payment processor added, map the fields from the Form to the integration making sure your "Price" field is mapped to the payment processor Total or Price field. This will tell the payment processor how much to charge the user.
Below is an example of the Published Form showing the fixed Price field for the item. When your end-users click Submit Form they will be taken to PayPal to pay the fixed $5.00.