The person you replied to has a lifetime-license, so no need for the clients to have a separate plan. Edit: Only thing where a separate license is needed afaik is the Download/Offline Watching feature. This will not work if a plex license owner adds a new User. Old/Existing Users can still use the download function. Here Plex made a change i think around 2 years ago.

I converted lots of my newsletters to rss with kill-the-newsletter.com . When i am in the mood i check the categories (art, shopping…) in my rss-reader for discounts or updates. I also added ebay-sales of prints from my favourite artists with rssbay-net .