A couple of site sponsors I checked quickly have stock of Sig P228 or P229 (assume 9mm) magazines: Marstar at $35 and Questar at $48. What's it worth? Well, your name isn't Questar, so you might not be able to convince someone to pay you full retail, but maybe you will. A very few people collect modern pistol magazines, so if it's in new condition and it's a scarcer type that they don't make any more (the 228
is dis-continued, replaced by the 229), it might be more, but it's a tough sale. Post a picture and someone might tell you it's a good one.
Generally, mag.s for work-horse pistols are treated as disposable commodities. If there's no shortage (ahem, PMags), the price is fairly stable.
I assume that this mag will also fit standard P226's too.
Well, it will technically fit in a 226, but it won't
work. The 228/229 have almost the same dimensions all around as the 226; basically you're looking at a 226 slightly shrunk in the slide and barrel length, and grip length. Thus the shorter mag. won't reach to feed in the longer grip, but going the other way does work: although the longer 226 mag. will poke out of the bottom of the 229 a bit, it functions.
