"gregcotellc.com" has CZ83 .380 Factory mags for $40.95 ea in stock.
I just saw the CZ83 magazines (unfortunately I just purchased four of the faux 'Mfg. CZ' mags) on Greg Cote's site
http://www.gregcotellc.com/cart/index.php?main_page=product_info&cPath=173&products_id=1413 last night while buying four Mecgar Hi Power 13 round 9x19mm magazines.
He really has a good selection with a great deal on flat rate shipping. I have never dealt with him before, but it is now the first place I will look when shopping for ANY new magazines.
On a related note, I had a day off and could not wait any longer to give a couple of the 'Mfg. CZ' magazines a try for the first time, despite below zero windchill on a 6 degree F. morning. I loaded each of them with twelve rounds of 9x18mm Brown Bear for my CZ82. Feed, firing, and ejection all went flawlessly, although neither one would lock the slide open after the last round. I will take a look at that issue sometime in the next week or so, but for a lower priced 'range magazine' I was satisfied with the 'Mfg. CZ' mags today.