If we go off of Sony's pricing of the PlayStation 4 when it first released in 2013, we could be looking at about US$400 for the PlayStation VR.
Of course, it should be noted that this will be on top of having to have a PS4 as well, so the real price for a full Sony VR system would add up to be around the $800 mark.
Still, that's something that all other VR headset makers will have to face, as the Oculus Rift, Razer OSVR and HTC Vive will need at least a powerful computer to work well, though Microsoft's HoloLens won't need a PC connection or phone to operate.