Dont buy from cyberpower, build one yourself it´s cheaper and better.
Not necessarily. If you choose the right components from the customize list they can be just fine and its almost impossible to undercut their buying power for said components. I've never bought from they but a friend recently did and he got a pretty nice rig for not a lot of money. That's only if purchased directly from them - if the OP is buying from a third party it is what it is of course.
That $35 EVGA 500W is a good choice.