Jason here from Shopify Support.
At the moment, Shopify accepts valid credit cards only. The prepaid cards typically aren't accepted because the card needs to have the ability for international and recurring payment features, which most of the prepaid cards don't have. Here is a detailed guide on the billing information required.
If there’s anything else I can help you out with, please don’t hesitate to reply back and I’d be happy to help out! Alternatively, you can always give us a call or start a live chat at any time. We're open 24/7 for your convenience and always happy to assist!
All the best,