The original SCO Group went out of business and the rights to the OS has changed hands a few times. I got my copy from the previous owners and all I had to do was sign up for and account and then download a copy. You can still use it without a paid license but you obviously don't get any support.
Good god almighty, don't go near SCO. Opensewer is what it was known as when I was using it. Solaris might have been known as "slowarse", but at least it works and is supported. The only support you'll get for OpenServer nowadays is from comp.unix.sco.misc, and the best advice you'll get from *there* is "use something else".
The OP wanted to try a real version of UNIX and I gave him an option that he could try for free. No need for bashing (just like every other *nix thread around here.) SCO is still out there and still needs support whether you like the OS or not.
Not bashing, as such. A lot of it depends on how much stock you set by it being "real Unix" - after all, if you want to go "real", you could always run "ancient Unix" on an emulator, or even on real hardware (
http://www.nordier.com/v7x86/index.html). The point being that OpenServer is way, way out of date, and doesn't support much of what is now commodity hardware. I know; 10 years ago I had clients struggling to keep ageing boxes alive because OpenServer was stable on them (and really struggling - to the point of having motherboards re-capped, and hoarding stocks of "known good" PCI cards) rather than risking migrating to newer hardware.
Realistically, if you want a "modern", "real" Unix and don't have $$$ to spend, you either use OSX or one of the (sadly) now unsupported OpenSolaris distros. But that's probably not what the OP wanted (especially OSX, which, although a "real" Unix, doesn't always play nice with current *n*x tools). If you want a "modern" Unix and you don't care about the brand, you're as well off with FreeBSD as anything else.