Sod HL3, I want Portal 3!
There already is cheap VR, it's called the Oculus Quest, or a PS4 Pro with PSVR. VR headsets are not expensive (compared to a half decent gaming monitor), it's the high end graphics cards required to drive them, although you can run some of the library with less powerful cards.
There's also no point in having an OS less computer if VR is your aim. Unfortunately VR is absolutely tied to Windows 10 at the moment for any sensible use.
(A limited number of VR games will work under Wine. Windows Mixed Reality absolutely needs Windows 10, and you'll likely be using SteamVR for some programs too. Oculus Rift will technically work on Windows 7, but it's a pain, the best platform is Windows 10. Haven't used Vive.)
Biting the hand that feeds IT
