what type of freon does a 1996 buick use?

I want to say is the R34 a but just call the auto parts store and give them your make and model and they can tell you what kind you need

It takes R-134a. Tom is right, you can't get R-12 anymore...Technically. There are a very few shops that have certified individuals (very hard to get certified anymore) to charge 1992 and older cars. If I remember right, that stuff was over $1000 for a 30 pound tank of the stuff because of the taxes due to EPA regulations.