Go to
www.imaca.org and spend $15 and a few hours to take an open book test online. You will then download a printable certificate that you can use to buy R12 without violating Federal law.
You then can go to any number of sites and buy it so that you KNOW that it is the real thing. I buy from
www.refrigerantsales.com.
R12 is coming down in price while 134 is going up, so it is now, more than ever, the time to stick with it for the cars designed to take it.
Good luck,