I just deployed my first app to render. Was a good experience.
However, they delete your database after 90 days if you do not have a paid plan. From https://render.com/docs/free#free-postgresql-databases
"Render’s free database plan allows you to run a PostgreSQL database that automatically expires 90 days after creation. Free databases are suspended after 90 days (unless they are upgraded to a paid plan), and are no longer reachable at this point."
The paid plans do start at $7, and you can share a database across many apps, though.
And if you have static site or a site without a database, it looks like it is forever free.