Gaming PC under $500

[ahoragi]

My mom's pc is going bad. It's a HP and not worth fixing so I will give her my current gaming PC (2012), which has been flawless and I will get another one to use. I went to college for Applied Computer Technology and learned to build computers but this was back in the early 2000's. Technology has improved over the years and I am very behind in the current tech. Can someone recommend a PC in the $500 range that will handle most games well? I am mostly interested in GTA5, Avatar the Game, and maybe some zombie games but nothing that requires top of the line systems.

I have a 40" 4k TV monitor if that matters.

Any help appreciated!

Thanks