I would start by saying that, as a person who had little knowledge about building a computer, but ended up doing exactly that, building is definitely the route i would take when building a Virtual Reality capable machine.
Couple of reasons for this:
- You get exponentially more power for your money.
- I personally cannot bear to spend more than necessary, and market pre-built gaming computers generally have a large markup.
With that out of the way, Oculus actually have a recommended list of computers here on their site. One that sticks out to me in the kind of price range you are mentioning above is the Lenovo IdeaCentre Y700.
The first in the range of these models actually starts at $649, which should have plenty enough power to run VR games.
There is actually a reason why I would recommend this over your $650 Cyberpower PC, (some people are not going to like this), but it has a NVidia GPU. In my experience, most (not all) VR experiences run much better on NVidia cards, but don't hold me to that as I have no solid or documented proof, I have tried both and I personally preferred the NVidia experience overall.
Another point to mention is that this computer sports an Intel processor, but that AMD vs Intel is a very contentious topic, and I don't feel it is my place to start an argument on that. (I recommend Intel by the way :p)
I threw together a price on PCPartPicker, but for the ease of purchase and performance, I couldn't recommend the Y700 more, it seems like a really good deal.