Role Based Access
One of the simplest ways to control access to groups of information is to give a role permission to the content using a module like Node View Permissions, which controls access to content types based one role. This role would be sold using Commerce License (part of the Digital Commerce Suite) and the role license plugin that it comes with. A couple of examples of what this could let you do is:
- Provide premium content on a blog by creating a second content type and using that for premium content.
- Sell subscription access to an online catalog of magazines, videos, or audio files (which would be their own content type).
Paid Content Creation (Publish on Pay)
With Drupal, you can assign permission to perform specific actions on content types. They can be used in tandem with custom rules or code to create any sort of for-pay content publishing (e.g. jobs, classifieds, auctions, etc.) Here is an example for selling node creation with Drupal Commerce.
Selling Access to a Single Node
Here is a walkthrough for selling access to a single node. This might be useful if you are wanting to sell the content itself, instead of a digital download. You could implement pay-per-view networking profile or paid contact forms.
Selling Access to Organic Groups
Other Role Based Possibilities
There are numerous access control modules available for Drupal. Using the Digital Commerce Suite, you can immediately implement anything that can be done with roles, or you can craft your own solution.