Your options are limited, you could: Become certified in A/C repair then be able to purchase at shop rate, attempt to smuggle into the US from other countries, or continue searching mom-in-law's basement for the rest of the case of freon. Virtually unobtainable for the DIYer in this day and age.

Typically I spring for the cost of R-12 whenever I need any A/C system topped off. Last time I paid shop rate of $35/pound.

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.