Just scored 10 surplus Check-Mate mags off GunBroker for $100, unpackaged but supposedly unused. I know they're not OEM or Mec-gar but the ones we have at work have been fine so I figured for $10/each they'll be decent range mags. Here in Colorado, even though I'm exempt from the mag capacity limit, replacing mags over 15 rounds is still difficult and expensive ( even in a free state 17s and 20s are north of $40) so the factory 17s and Mec-gar 20s I have get vetted with the gun and only used for carry and house duty.