$40 for a can of Freon? I think /not/.

You might check out this. Enviro-Safe R134a R12 Replacement AC Refrigerant + Dye 3 Cans Freon R-134a R-12 for $19.95 plus shipping. I haven't used it but I know a couple of guys that have and swear it is good stuff. Maybe you should do a Google search and see what others have to say.

http://www.ebay.com/itm/Enviro-Safe...Parts_Accessories&hash=item3f1750096e&vxp=mtr