What I get from buying a "Linux machine" isn't just avoiding purchasing a Windows license. (Those tend to be paid for by all the software bundling, anyway)

What I get is a computer that is tested on Linux and thus is known to have well-supported hardware.

I've had plenty of computers that "work" in Linux, but some of the smaller details (suspend/resume, advanced functions of the audio hardware, etc) would either not work, or would only work after considerable effort.