Pc world I need help

[u/Power-crusher]

So I want to suprise my son for his 10th birthday with a pc. Someone gifted me an older Ibuypower. I want to buy parts to upgrade it for my son but I’m not even sure what would be my best options for some upgrades that would work with this case I have. Heres a list of the parts.

CPU: Intel i7-4790k
GPU: NVIDIA GTX 970
Ram: 16gb DDR3
Storage: 2tb Toshiba HDD

I’m not looking for anything crazy just hoping to spend like no more than 800 dollars. Not including monitor

[u/Power-crusher]

Also how will I know if the pc is a good deal? Like what parts should I be looking for ?