If your payment form needs are very simple, you can probably use the free plugin. It works with any Gravity Forms licence from Basic up, so it’s a very low-cost and easy way to start accepting payments online.
- fill in your Windcave settings
- create a form and add some fields
- add a Windcave feed and configure the mapped fields
- test your form with the Windcave sandbox
Make sure that your form has a Product field with a cost, so that there’s something that costs money.