To use PayPal with FoxyCart you'll need to have PayPal's Website Payments Pro (US and UK only). There are only a few steps you'll need to take to use PayPal's Website Payments Pro with FoxyCart:
Profile tab and click API Access in the “Account Information” column.billing_api1.foxycart.com, check all the checkboxes, and submit. (Or, if you already have another API permission granted, click “Add new permission”, then do the preceding.)Testing is always a very good idea. You can use the default FoxyCart sandbox account for testing (in your “Payment Gateway” settings), but this won't allow you to see all the transaction details. When it's necessary to test things more thoroughly, you should set up your own PayPal Sandbox account.
While you're using a PayPal Sandbox, you can run test transactions using the test card number 4242424242424242, with any expiration date in the future. NOTE: This card number is for testing and will not work on a live PayPal account.
If you'd like to test things more completely you can set up your own PayPal Sandbox account. It's a bit involved, but once you set up a sandbox account, follow the steps above but grant API permission to sandbox_api1.foxycart.com rather than the billing_api1.