I run a language learning app* on a single VPS, for free. I'm not sure if you can still get it, but Oracle used to offer very generous VPS for free. I have a 4 CPUs, 24 GB memory VPS that I'm using for several things, including running the backend and the marketing site for that app.
I installed Plex but ended up not using it, so I removed it.
Oracle's free tier ARM VM's specs were recently halved so now they only give ARMs with 2 CPUs and 12GB of RAM [0].
Still great value though, have my app's website and associated infra on one of those 4CPU/24GB in "pay-as-you-go" mode and never ever reached the paying threshold.
[0] https://docs.oracle.com/en-us/iaas/Content/FreeTier/freetier...