I realize the irony of doing what essentially amounts to advertising on a socialist site, but I wanted to put this out there for comrades that are low on cash, but want a gaming pc. This is a pretty difficult deal to beat in terms of bang-per-buck. The only thing I it's lacking is a little bit of memory, but that can be upgraded at any time, and it'll probably play most modern games short of Crysis very well right out of the box.
It'll come with a keyboard and mouse in the box. They'll be pretty basic, but they might suit you just fine. I would wait to see what they're like before you replace them. Here's another 8GB memory stick you could add to the one it comes with: https://www.newegg.com/g-skill-8gb-288-pin-ddr4-sdram/p/N82E16820232419
Edit: as for other stuff you might need, this will get you started. 512 GB's will probably turn out to be a bit small after some months down the road, depending on your habits.