Only US$225 at Etronics, shipping included. Good reviews at audioreview.

10" cone driver
250W Amplifier
20 to 160 Hz frequency range
Advanced Active Servo Technology --is an amplifier/speaker system utilizing negative impedance feedback in the amp and a Helmholtz resonator in the speaker to provide strong and accurate bass.
BASS Selector
Yamaha's QD-Bass Technology
Magnetic Shielding
Continuously variable high-cut filter sets the highest frequency the subwoofer will deliver. It can be set anywhere from 40 to 140 Hz.
Volume Control
Signal Sensing ON/OFF: When the subwoofer detects an audio signal, it turns its power on.
Phase Normal/Reverse Switch
Dual Inputs-- allow the versatile subwoofer to accept either line level or speaker level input signals.
Three-way speaker terminals
Black Ash finish
The YST-SW315's cabinet is constructed of thick MDF to increase rigidity and reduce vibration and resonance.

Driver 10" down firing spruce cone driver.
Amplifier Built in 250 watt Yamaha PWM type. Advanced Active Servo Technology.
Frequency Response (-10dB): 20-160Hz
High-Cut Filter Continuously variable from 40-140Hz
High Cut Slope 24dB/oct
Standy Power Consumption 0.5W
Dimensions (W x H x D) 13 3/4" X 17" X 15 1/16"
Weight 42 lbs.

Two subs for $450. What do you guys think? Best Buy has them for $300 MSRP each + tax.

Actually, it's US$190 + shipping. In my case, shipping ( to CA ) is $35.

Depending on how big your room is and where you are you could get a HSU STF-2 from Comp USA (so I've heard) for $349. A much, much better sub. Do a search in the forums here, you'll see other people will agree.