For anybody living near Dallas, TX here is a great deal where you can purchase R12 for $10 a pound.

http://cgi.ebay.com/ebaymotors/National-30-lb-Freon-R12-R-12-NIB-Dallas_W0QQitemZ8039103987QQcategoryZ46094QQrdZ1QQcmdZViewItem

I just checked the refrigerantsales.com web-site and a 30lb cylinder of R134a is going for $349.

At least at bulk rates R12 is now CHEAPER than R134a.