In order to use  paypal for usage billing, need to following steps.

  1. Click Settings Payment methods  → Paypal Account                                                                                                                                                                            
  2. Click the button that says, 'Authenticate OrderCup'. (This will take you to Paypal to sign in. Once you are in Paypal, click on the "Grant Permission" button, and you will come back to this screen.)                                                                                                                                                                                   


Here is a sample screenshot of the completed payment method.

NOTE: Paypal transactions are subject to a payment processing fee of 3%. The recredit amount is credited immediately to your respective OrderCup Shipping Account.