Store bought versus indy installed freon

[PETERPNYC]

My 93 400 sel had the evaporator / drier the whole shooting match replaced in 2004.

At the end of last summer it stopped blowing cool , and I brought it to my Indy. It was low on Freon and he put about 1lb in it , then realized his Freon can was empty and it was after 5 Pm so he did not charge me anything and said come back another day and we will fill it.

Now its 8 months later and it works well so far,but with summer coming , I brought it to my new Indy to fill. I figured when it gets warm running it half full is probably not a good idea.

He said he was out of freon till next week and said I should buy a can of Freon at Auto Zone or someplace like that , and fill it myself.

Does anyone agree or disagree with just adding a can without knowing how much is in there. He even said he would help me to put it in, when I bring the car next week to change the motor/tranny mounts. If you guys think its ok , is it a simple thing for me to do on my own?

Or should I insist on him filling it at around $60, versus just adding a can from a store myself or with his help.

Since I have solved my bogging down under load dilemma , I have decided to maintain my car better, and am going to do maintenance work before problems develop. It has 83K miles and still runs like a dream.

I changed plugs, caps/rotors/ , coils and 3 plug suppressors , fuel filter, brake booster hose , radiator cap, had MAf cleaned , and now I am going to change motor and tranny mounts.

Let me know your thoughts on Freon filling