In your admin area, in Payment Plugins, you will find Free Checkout.
This enables your customers to checkout for products that are free (basically, for products that have a price of 0.00 in the admin area).
If you are using reward points, you need to enable Free Checkout as a payment option in your admin area > Payment Plugins. This allows your buyers to checkout when their order total is 0.00 (when they are using reward points to cover their entire purchase). Free Checkout is only presented to your buyers as a checkout/payment option when the total amount payable is 0.00. If the total is anything over 0.00 then the Free Checkout option will not be shown to buyers.
If you don't enable Free Checkout, your buyers will be prompted to pay 0.00 with your normal payment processor (for example, Stripe/PayPal), but they will get an error message.
You should consider setting a minimum total value and any other payment options that you use. Setting a minimum payment amount of 0.01 or more will stop Ozcart checkout from showing the chosen payment gateway as a payment option for 0.00 orders. You might like to set the minimum payment amount higher than 0.01 to avoid payments where the payment amount is less than the fees charged by your payment processor.
To set a minimum total value, go to your payment processor in Payment Plugins, find the 'Total' or 'Minimum Order Total' field, and enter a number there. You can hover over the 'Total' or 'Minimum Order Total' title for more information.
