Hi. Its my first time here and I just found out about Cubase, so please forgive any inconvenience from my part. I recently found the Unsupported Software Downloads Page for Cubase (I couldn’t put the link here), which includes old Cubase versions, all the way down to Cubase 4, from what I could see, and my question is: are old Cubase versions, such as Cubase 4, free to use? All I see in the page is an installer guide and files, without any payment-related instructions, so I had to create an account here and ask. Thanks in advance 
Hello and welcome.
Cubase versions are never free, that includes older versions. They all have the user license check system still built-in and will only run on a properly authorized machine.
The downloads are available for those of us who have a valid license and want, for whatever reason, run an older version of Cubase.
Alright, thank you! 
If you have the latest (v15) you can roll back as far as v12 of the same or a lower package (Pro, Artist, SE, etc.) and no dongle is required. In short, anything from v13 forward, you can roll back as far as v12 with your license (even have the older and newer versions installed at the same time on the same machine(s)). You will need to be connected to the internet to activate it (possible to do for an offline machine, but you’ll need something online to complete the registration process).
All versions up to v11 needed a special dongle with a registration key on it. Same scheme in that you can use the dongle to run the newest version you registered, and all equal and lower versions that came before it. Most will have a USB dongle, and the same dongle will work on Windows and Mac versions.
Upgrading from a dongle version (up to v11) to a newer dongle free version required the dongle being plugged in, and the upgrade process touched the dongle key in a way that prevents attempting to ‘double upgrade’ the same account/key. Such a user can still use the dongle to run the older versions up to v11.
Those who got into Cubase with a brand new license for the first time from v12 forward don’t need a dongle, and probably do not have one. Without a registered dongle versions older than 12 will not work. Those who never had a dongle probably never will unless they find one on the used market with keys already on it.
The old eLicenser servers for maintaining dongles has been taken offline as far as I know. If you have a broken or lost dongle situation (and the dongle is still properly registered on your MySteinberg Account), one would need to contact support to see what they have to say (maybe they can fix/replace it, set you up with an upgrade voucher to a dongle free version, or maybe not?).
I’m guessing that the OP doesn’t own any version of Cubase.
The only “free” versions of Cubase are the AI (no, not THAT kind of AI) and LE, both of which are extremely cut down versions and are usually bundled with audio interfaces.
Yea, I found out Cubase existed just today, cuz of a YT short where a guy made a pun with U-Bass (ukulele bass) and Cubase ¯\_(ツ)_/¯
If you want to try Cubase, Steinberg offer a 60-day free trial of Cubase Pro with full functionality. They also have regular sales.
Sign up for the news letter. You’ll be notified when the sales are on. You don’t get any spam, either.
Old versions of AI and LE can sometimes be picked up with S/H hardware sales as long as the original unused download code is explicitly included and still unredeemed. You would also find it tough to install them since they closed down the eLicensing system.
Cubase Elements is a very good deal. I have been using it as my main DAW for close to 5 years.
You can also buy a used Cubase license on knobcloud for a fraction of the original price. It’s safe and no different from a new version. Just make sure to read Steinberg’s Reale Wizard beforehand.