I actually have one of these - Samsung Gear VR, 5 Million Shipped.

[Turkish]

Low barrier of entry, readily available, easy plug n play, surprised there's not more alternatives to it.

This is why $900 PC HMDs are DOA. "bbu bbuut it only took me 30 minutes to set up! U only need a gtx 1060! Everyone has 3 available Usb ports! $200 Oculus Touch enhances the experience!"