We are in the process of packaging the plugin for deployment through the WordPress plugin repository. This means all WordPress users will be able to download the full plugin for free.
In the meantime, you can get access to the current version of the plugin (which is very much complete and deployed on several active websites) by signing up for our premium support membership here… just $10/month right now*.
More information coming soon.
* UPDATE: This is an old news post from when PMPro was first in development. The plugin, and all of our code, is still available for free through the WordPress.org repository or on GitHub. We have several paid plans on our site to offer support, automated updates of certain add ons, and other services and content.