Free credits and Paid credits are exactly the same, except free credits are provided on a monthly basis (1st of each month) at no cost to you. It's our way of letting your experience how useful RefNow is for your organisation.
Paid credits are topped up based on your next billing date (found in the Admin -> Invoices page). If you don't have any paid credits you can set them up by visiting the Admin -> Billing page.
We hope you enjoy using RefNow.