If you already have the $9.99 Basic plan, you can keep it.
I've been putting off having a local copy of the series and movies I watch because I still can access them quickly and cheaply enough in some streaming service, I think it's time to plan ramping up my selfhosted setup.
Plexshares are soon going to be the only thing people will need as less money and value without bs politics and taking customers for granted and as fools....
If you use a "public" Plex share (one that you find online and pay a monthly fee for), Plex will eventually find you and suspend your account.
A safer approach with Plex is to get a cheap server (assuming you can direct play on most client systems), get an unlimited Dropbox team account for storage, use rclone to mount Dropbox on the server, and auto-download via Usenet using Radarr, Sonarr and Lidarr. Split the cost across a bunch of friends.
Or just use Weyd or Syncler plus a Real Debrid account. Real Debrid caches torrents so they're instantly available to stream at full speed over an encrypted (TLS) connection.
I'm not sure if either one is definitively better; they both have their pros and cons. Plex is probably the most popular at the moment, so colloquially the term "plex shares" is the most common term used for systems where you pay someone to share their media collection with you.