it is surplus store not available for others :) The guy in the original article bought a vehicle which just a step from "a 7-ton piece of junk" - at least it was playing that role for many years at the military base what it was bought from. The hardware in your post's link came from a kind of "limited access surplus store" which was used at the beginning. Currently a lot of the rebels' hardware, including armored vehicles and tanks, are in very good condition and of pretty good "model year" :) - for example among the rebels' main battle tanks are pretty modern, latest version of T-72 (still, in addition to the newest T-90, used by Russia (and only by Russia, ie. it hasn't been exported) ) with all the bells and whistles (navigation/targeting hardware, reactive armor, active protection system, etc...)
Note: of course not all the hardware is that good and new. Two other main sources of the hardware are captured (and in many cases i suspect actually bought while reported as captured as many people in Ukrainian army and government are reluctant, to say the least, to fight the rebels or are just corrupt - also check out the stories about "lost" and "prepared for sale to unknown buyer" tanks at Kharkov tank factory (cool photos just to get a scale of possibilities http://thehiat.blogspot.com/2012/06/kharkov-armoured-repair-... ) :) hardware of Ukrainian army in Donetsk/Lugansk region and the hardware the Ukraine left in Crimea which was trafficked into Donetsk/Lugansk.