CZ-82 magazines at Keepshooting - those are not CZ factory, but believed to have good quality and solid reputation.
$24.95
$19.95 per mag if you buy 3.
Use coupon code "catalog" for 10% off.
Priority mail shipping for 3 mags $$6.44
Total for 3 mags shipped with 10% off: $60.30
http://www.keepshooting.com/cz-82-magazine.html