What are Paypal payment restrictions imposed b Fastspring?

Please be advised that a buyer is only asked for a credit card if they do not have enough funds in their account to complete the purchase. If the customer has enough funds including the purchase price and taxes, a credit card should not be requested.

The exception here is for subscription products. Because of the recurring nature of subscription transactions, the PayPal funding source must be a credit card. In other words, if the customer is trying to purchase a subscription, Paypal credit cannot be used.