Not sure I follow. There are plenty of free distros of Linux and BSD, and many are easy enough to use, especially Linux ones. Anyone who doesn't need a particular piece of Windows- or Mac-specific software can set themselves up with one of these for free.
If the concern is making the UI look like Mac, you can find desktop environments and themes for Linux that aim to do that. (I expect you can do it in BSD too since it runs some of the same desktop environments.) There are even Linux distros like ElementaryOS that aim for a Mac-ish feel, though personally I wouldn't choose my whole distro based on a desktop theme since you can tweak that stuff on any distro. If you search for "make linux look like MacOS" you'll find plenty of sites with instructions.