The most I’d pay for a PC with Win 7/8/10 is $250. Just recently picked up a Dell 960 Optiplex, Win 7 Pro, 3GB processor, 4 gigs ram, DVD&BluRay, 360G HD on EBay for 60 bucks - included shipping & a mouse & keyboard. Works just dandy, but I might spend 30 bucks to put in 4 more GB of RAM.
These were from Lenovo
I am sure they are on eBay for less
I was buying these for clients to use in their businesses