Walmart has the Merkury Innovations Merkury Evo Next Vr Bundle on clearance for $4. I've checked a bunch of zips and it's widely available. Hurry! My local store only has 126 left!
This is a rebadged Onebox VR. The bonus is that it comes with a bluetooth controller. Even if you don't want the VR headset, you can use the bluetooth controller to play Android games.
It's an OK headset. It has independent IPD and focus adjustments per eye, it's easy to fit a wide range of people. Not the widest FOV but the lenses are clear for what they are. Some people swear by their Oneboxes claiming they are better than a Gear VR or even a Rift for image quality. I'm not one of those but for $4, it's decent enough. Better than holding up Google cardboard to your head
Online link for reference and SKU. Walmart online is OOS.