Re: Variable Pricing - 'Name Your Price' modification
Explain to your client that Amazon actually does not store the credit card information and most online stores don't. What they store is an authentication token from the payment gateway that allows you to continue to make additional transactions over and over.
This is why when you enter a new billing or shipping address (some credit card BINs require that the shipping address is on file with the bank) on Amazon they require you to enter a credit card again. Many payment gateways support this style of vault payments such as Authorize.net CIM, Braintree, USA ePay etc.
It's a common misconception that these companies store the full credit card information when they do not. They just store a transaction token that they can keep using. I could be mistaken but I think it's now actually in violation of laws to store full bin information even for ARB (recurring billing).