Amazon経由での決算が終了した原因として同社が提供する決算サービス「Amazon Flexible Payments」が終了したためであり、Cydia側の問題ではないとのこと。


Amazon Flexible Payments closed its doors as of noon today US Pacific time, and, frankly, I must say “good riddance”: I have had tons of issues with them, from technical blunders to credit fraud (enough that I actually recommend closing your account!); they even were not able to do simple things like update the address they have on file for my business despite me trying to get them to send my tax forms to “actually me” for years :/.
Amazon has a replacement solution called Login and Pay with Amazon, but it is both cost prohibitive and, to be quite honest, still run by Amazon, which is a major turn-off for me at this point :/. (Humorously, I actually only looked at its pricing last night to notice how expensive it was, despite having been arguing with Amazon about this very service since before they had made it public that they were even in the process of building it.)
FWIW, on the “easier to keep up with” comment: one of the big reasons people used Amazon Flexible Payments in Cydia is because of the support Amazon Flexible Payments had for “multi-use tokens”; this allowed users to log in once, set up a payment authorization, and then subsequent payments in Cydia no longer required logging in via Amazon. A better version of this is now supported by PayPal via Merchant Initiated Billing.
For those users who absolutely cannot have a PayPal account for various reasons, I will have a good solution for you in the very near future. (I’d hoped to launch with it today at noon, but I had not expected to get waylaid by not one but two jailbreaks from separate teams, and even to the extent to which it was clear we’d at least have an 8.4 jailbreak from TaiG, 25PP shipping a jailbreak with that known passcode regression really sucked.)