Well, the first link has been in stock most of the day, now from midway? Perhaps as it becomes obvious that a high cap ban is going nowhere the craze will ease a bit.
MidwayUSA has some stainless steel magazines for $13.99, limit two.
AR-Stoner Mag AR-15 223 Remington 30-Round Curved Body Anti Tilt
PSA is now out of stock.