You can also find mags on Gun Broker. Be sure to search for 82 mags. The mags listed for sale as 83 mags are quite a bit more expensive.
That being said, don't let the cost of the magazine make to pull up short of buying the 82. I have two. Both shoot and handle great. The 82, and the civilian model 83 for that matter, is a great little gun. I loved my first one so much, I bought the second @ 2 weeks later. I carry one of them in a Kholster Crescent holster under a tucked shirt. The 82 conceals well and with a good gun belt, the weight is evenly distributed.
I also got lucky in that both of my 82's were in almost flawless condition. The first, which I am planing to have refinished, is in @ 95% condition while the second is in 99% condition. The second one stays in my wife's bedside safe. It's there to use if needed but I refuse to carry it because I want it to stay right where it is in terms of condition and appearance.
I've toyed with buying another one which my LGS has in stock for $240.00. It is in fair condition and would make a good project gun. I just can't afford to do it right now. If my wife finds a teaching job this year, though . . . .