you can get your 609 card online and the test is open book with a 3 hour time frame to take it. In other words you would have to be pretty stupid to fail the thing. I got my card several years ago before the online test was there to take but still was not hard, pretty much in the same line as getting a class A CDL drivers license. Read the book, pass the test.
However r12 freon is no where near $15.00 pound (can) here in Florida. Best price quoted was $55.00 and that was with a "dealer" discount from the parts stores. Ebay you can find it for less but you also stand the chance of being ripped off by a seller. It has happened to me twice this year and from people with 100+ feedbacks. paypal did jump in on one and refund, still waiting for ebay fraud to send me 75% of money lost in another deal.
Duracool is not a blend. It is straight hydrocarbon based, IE propane. It is not made to be recovered with r12 and although it is illegal you can vent the stuff without killing the ozone layer. If you convert your system should be labeled by law telling any tech what it is filled with. This is for their protection since some of the old leak detectors used an open flame. Not a good idea with a coolent that will burn. It also stops contamination of existing r12 freon that has been recovered. The recovery thing is is of the biggest ripoff games played here. No shop will claim they use recovered r12, they charge for "new" stuff and charge you $75.00 and up per pound when they are using r12 from their recovery system. This may be the r12 they removed from your system to repair it and then charge you full price to replace it.