Can the website process prepaid credit cards?

Fullsteam Payments:

Prepaid cards will work as long as the card has enough to cover the full balance of the Order. If it does not have enough to cover the full balance, it will return an insufficient funds error. 

Other Gateways:

As long as your Payment Gateway is configured to accept prepaid cards, they should work with no problem. If you are seeing declines, we would recommend reaching out to your Payment Gateway to inquire as to the reason (note that commerce7 simply passes the credit card and payment information entered - and waits for your gateway to respond with Approve or Decline). Your Gateway should be able to provide a concrete explanation for the declines.