I would say its value is in the $600-$700 range. Mags show up on ebay occasionally. Morons show up on ebay, too. Some guy paid something like $90 for two aftermarket Combat Master mags, even after I warned him they weren't factory mags. If you are going to pay collector prices ($40-$50) for mags, be sure they are real. All Combat Master mags are stainless, and they say ".45 ACP", not ".45 AUTO" on the bottom.