As someone who's had to chase down Sig mags in 220 226, and 229 in pre and post ban configurations and three different cal...I can say the following.
1. Pre-bans for any of those listed are going to cost you within a dollar or five of $38.
2. Post ban mags (you naughty kids..I wouldn't risk it!) will cost only a few dollars less.
3. Brand new mags, compared to your old "prebans," will make you cry at their beauty.
4. ALL BRAND NAME SIG MAGS ARE OVERPRICED
5. ALL OFF-BRAND SIG MAGS SUCK (performance-wise)
6. The "quick" among you already known your f'ed in this state if you want Sig mags.
7. The less "quick" among you won't realize this until point #10
8. Even older "brand name" mags are well built, which lessens the sting of a $40 mag.
9. Yes, we've all found rare "$20 buys" but we're discussing day-to-day availability here.
10. Love your Sig, cause If you need Sig Brand Mags in MA you are gonna pay.