Gentlemen,
GunMagWarehouse has M&P Shield 9mm 8-round mags on sale for $18.99. I ordered one, it arrived, packaged in the original S&W M&P plastic container. It is the real S&W M&P 9mm mag.
Shipping was also free.
I thought that I would pass this along to the forum members.

Here's another smoking deal if you need 5 mags and 5 boxes of ammo, $99 with free shipping. Weekend only.

Five S&W M&P Shield 9mm Magazines & Five Winchester USA 9mm 124gr FMJ 50rds Boxes