Costco has the Klipsch R-12SW Reference Powered Subwoofer for $189.99 after an instant $60 discount.
Free shipping (ordered mine today, to be delivered tomorrow).
9/2 to 9/27 (or until supplies last).
Product details (from the Costco website):
Spun Wire IMG Woofer
Low Pass Crossover and Phase Control
Price on Amazon: $229.88
I can't find it really anywhere else (older model? specific to Costco? I don't know).
In my setup this will replace a smaller Polk Audio PSW110 10-Inch Powered Subwoofer that died.