I just purchased 6 more Taurus factory magazines from Cabela's at 75% off, which is $9.88 each (plus tax and shipping).
I had previously purchased these magazines when they were "only" half off for $19.88, and they are all perfect, and genuine Taurus products.
My guess is that they may be limited quantity - limited time deals.
Here is what they have:
Cabela's: Taurus Factory Magazines
MIL Pro .45 ACP 10 round (PT 145)
24/7 Compact .40 S&W 11 round (these also fit the PT 640 Pro with the simple modification of filing down the top of the plastic magazine base about 1/16")
MIL Pro 9mm Flat 10 round
MIL Pro 9mm 10 round
Click on image below for full size image of the sale page: