I’d be interested in this also.
So would I! This would be great to implement
Although, there could be a simple alternative if your willing to dispense passwords and to just password protect a page…
IE. Person A pays X dollars to learn password to the subscription only area and you can just password protect it in the options
However… the drawback is that if Person A or B or whoever tells the password to Person ZETA then its leaked…
The (Suma) plugin adds access control and subscription management functionality to WordPress. With it you you can build subscription-based websites and other paid-content information hubs.
It restricts access to content on the site (e.g. posts, comments, pages, etc) which only subscribers can view. Non-subscribers can register to become subscribers by choosing a recurring billing plan (as defined by the administrator) and entering a payment method. Suma supports both PayPal and Credit card payment methods and manages all recurring billing for you.
More information is available at http://sumaplugin.com. There is also a free download version available from there.
