Is SQL*Plus free to download and use, or does your organization need to purchase a license. And if it is free to download and use, where would be a safe place from which to download it? I need Oracle version 19c Release 3, although I can get away with Oracle version 11g or higher.
You can download only SQLPlus via the 'lite' Instant Client offering.
It's called the SQL*Plus Package, look for a file download similar to -
instantclient-sqlplus-windows.x64-21.6.0.0.0dbru.zip
There's no installer, just unzip and start using.
You can find the download for the Instant Client on Windows here.
Is it free?
YES.
Instant Client is free from OTN for anyone to use in a development or production environment. However, customers can only call Oracle Support if they already have a standard support contract.
If you like a command-line interface, but you're looking for a more modern feel, and powerful features and commands, we also have SQLcl - which is again, FREE.
See if you can spot the differences...
Disclaimer: I'm an Oracle employee, and a product manager on the database tools team.