At this time, products must have a price >$0.01 to be added to the checkout. I understand this is a requirement of payment processors (Visa, MC, PayPal, etc.).
However, if Manual Payment is our only Payment Option, then payment processors are not affected. In this instance, it would be very helpful to us to be able to checkout products that are free ($0.00), and make use of the wix-pay API.
Hoping this combination of free product/Manual Payment/wix-pay API might be possible now or in the future. :)