I agree that it is still available, albeit very expensive. I got the impression that he was trying to charge it himself. I have been told that the DIYers can't get it themselves, that only licensed shops can.
A mech friend said R12 can be bought.. it is brought in from Mexico in the underground market. He also told me that what a person may be buying is probably contaminated R12 or even worse not R12 at all.
He will not do any R12 work unless he knows the car and the owner and the air conditioning history. He said he does not want to cantaminate his R12 recovery system. I had a small leak repaired and filled with R12 2 years ago and the aircondition is working great.
I know that when I had the repair and fill done that the shop recorded the amount recovered and the amount used to charge the system and it was entered into a State computer data base.
I was looking at this air conditioning stuff last week and came across this mentioned as well. Other than the people selling it, I don't think good things were being said. Go to one of the search engines, I was at www.google.com, and enter the term. You will see numerous posts.
You can't recharge your system unless you evacuate it first to a very high vacuum level, hold it to check for leaks, then charge it with the correct amount of refrigerant. Only A/C shops and dealers have the recovery/evacuation equipment, and most of the "no-name" alleged replacement refrigerants (which are not approved for use) contain propane. You can't do it at home, and you don't want propane in your A/C system. Take it to a licensed A/C shop or a dealer and have it done right.