608 certification will get you R22. 608=HVAC, 609=MVAC

I bought 30lbs R22 a few years back for $70. I priced 30lbs of 134a the other day and I think they said $175? I was just checking and don't remember. I am guessing that 30lbs R22 would be in that range now.

This I am pullling off of the top of my head and never had much experience with, old refrigerators were often R12 but had less than a pound of refrigerant. Small old window units were R12 and had a little more ref. Larger window units were R22.

I only mess with this stuff when something needs work and don't keep current. The 608 certification was easy enough and cheap enough that I would recommend it to anyone with moderate DIY aptitude.

You might like this old thread:
http://www.peachparts.com/shopforum/showthread.php?t=126155