So you're looking for an extraordinary deal on a used industrial machining center? Even used, those machines go for about twice that, and up if the controls are anywhere near modern standards. Did you want to set up "drip-feeding" to trickle a huge 3D program into the tiny memory of an '80s-vintage controller? Do you have the facilities and heavy power to support those beasts? Are you able to evaluate the condition of a used mill?
Often machines like that have spent years making the same part, over and over again, so the middle of the ways are worn down but the ends of travel are barely touched; re-scraping is needed to bring them back into general use. People don't usually launch into these retrofit projects because they have nothing better to do; they're like you and want a much more expensive machine than they can afford. If you don't want to retrofit or spend the money for a modern machine, or if the answer to any of the other questions above is "no", then you might look for smaller but newer milling machines with PC-based controllers.