Plex is a software that organizes locally stored media. https://www.plex.tv/
It transforms video fields to a Netflix like experience. If you would like to know how to it specifically works, please look at the plex.tv site.
With only a Plex account you will only have access to the free stuff on Plex their own servers, this is basically pure shit. With us, you get access to our library, stores on huge servers with the most high quality hardware there is.
Since Plex is a separate thing from PennyStream, we can not prevent you needing a Plexpass for certain things.
Plexpass is needed for downloading content and to use Plex on mobile devices. We offer an easy workaround for android devices, contact us for that. For Apple you will either need the one device one time payment thing or a Plexpass subscription, which is $5 USD.
If you have any more questions, feel free to contact us.