system
A chat on subreddit /r/pcmasterrace
human
good buy for cheap, but idk about "solid base to upgrade on", for a real pc you would need to upgrade almost every part in that rig.
gpt
got the whole thing for less than the BIN cost of the cpu, used, on ebay.   

great deal! *even with the limited upgrade options*.  

$75 would normally get something like an ~~abused~~'refurbished' 3rd-6th gen hp or dell pizza box.