Packback does not store or retain credit card information on our site, which is a significant part of our security. We use a PCI compliant processor, Braintree (a PayPal company), to process all of our transactions. Braintree stores the information on their end, while Packback merely calls it to retrieve it so that a customer may complete purchase for access to their community.
This would be a similar user experience to that of Amazon or many other websites to make checkouts more seamless by allowing customers to bypass having to re-enter their information after each purchase.
More information about Braintree's security details can be found here!