what config for 3000-4000$? because if you buy older used servers you can have 10 or more servers for this price 
of course they will not be super energy efficient like ryzen or so, but... who cares if you have super cheap electricity... (10k bill /year for 100 computers (300k /3k))
of course they will not be super energy efficient like ryzen or so, but... who cares if you have super cheap electricity... (10k bill /year for 100 computers (300k /3k))