Question is: What are you going to play?
Because at that price, i’d get the AMD A12-9800 APU with an A320 AM4+ Board. That way you can upgrade down the line to a decent GPU and maybe the big R3/small R5, because AM4 will probably be around for a very long time. The Board is decent, as well as the APU. I haven’t found one in the U.S. though…they are only sold as Bundles, there are some in the EU for ~ 280 Euros including 8 GB Ram, but i’m not sure if they are shipped to the US.
Or you get this: https://www.amazon.com/HP-Pavilion-510-p127c-Desktop-Refurbished/dp/B01N4GCOLL/ref=sr_1_1?ie=UTF8&qid=1490354903
Same story, you’ll be able to upgrade to bigger CPU and a decent GPU down the line. Also, it’s cheaper, since at that price point, the mass production of these systems is considerably cheaper than building it yourself. Also, it’s a standard µATX Board and you even have an m.2 slot for SSDs. Funny thing is: Apparently this uses a standard SFX PSU, so you can even upgrade that down the line.
Personally i think, a self build system can’t beat a prebuild one at those prices. Unless you get on ebay and get some used stuff.