HTC's Vive headset is the cream of the crop when it comes to virtual reality headsets, and right now you can find the headset on Amazon for about $351 after a 20-percent discount is taken at checkout, with the price before discount putting the headset at about $439. Worth noting is that this is the price for a used model, though it does come Amazon and is listed as being in very good condition. The HTC Vive comes complete with everything you'll need to get started with room-scale VR in the home, save for the PC you'll need to power it of course.
Other than the PC though, the HTC Vive in this deal does come with everything else you'll need to get started, which includes the headset itself, the room sensors, and the Vive controllers which you'll need for most games. It does not come with headphones although you don't need them if your PC has speakers, but it might be beneficial to have a pair if you want the audio to be more discrete. One you have all the equipment you need to get the headset powered on and running, you'll have access to tons of VR games and other VR content through Steam and Viveport, and although the headset does come with its own controllers, some games can be played with an Xbox One controller that you would use for non-VR Windows games if you prefer this type of controller setup.