@myhero – We have 2 documentations for the 2 plugins. V2 can be found here: https://developer.tinypass.com/main/wordpress, while V3 can be found here: https://publisher.tinypass.com/tinypass-for-wordpress/
V2 is no longer supported – however it had the pay per post feature. The new v3 plugin does not have pay per post. This is because of WordPress’ hosting methodology. If you self-host you can use the legacy v2 plugin. The API does has it too: https://developer.tinypass.com/main/index However I should note that publishers earn more revenue from subscription models than from pay per post models.
@gourmetbooks – that is a good suggestion, I will pass it on to the developers.