Probably it will be free with limitation, very cheap with mid-range features, and more expensive for professional users.
Sorry, but at this stage, we wouldn’t like to disclose technical information. 
It’s really a challenging topic. We are considering collecting user-related code into a separate file. It mainly means event handlers. By default, the obsolete functions are not deleted but marked with an “orphan” comment. We are still working on it so it still might change. If you have any good ideas we are really open to it 