Value of 20rd AR18 Mags?
I don't really know the value but Thermold 30 round NIB are $10 each and 40 round 180 are available for premiums of $80
I may be interested in trade if I knew what you needed.
I am new here and navigation of the site is a learning experience.
I would say $35 to 45 range.
The two mags are both Howa AR18/180 mags, they are milspec in quality and are not that commonly found, I'd say they are worth at least $50 each if in good shape which these two appear to be. The black alloy Sterling 180 mags with a purple tint sold by Gun Parts Corp until they sold out were selling for about $40 the last time I checked and were not milspec failing when used in the full auto AR18, ok for use in AR180. The Costa Mesa 20 rd alloy mags should also command at least $50 and like the Howa mags are milspec and there arn't a lot around. The 40rd Sterling parkerized steel mags are 100% milspec and intended for the Sterling AR18, prices generally are $100+.
Looking at the base plates the one on the top is a Costa Mesa mag and the one on the bottom is a Howa mag. If you check the design of the lettering /markings on the side plate of the respective AR180s it's plain to see which is which.