One day only, Best Buy has the Polk Audio 12-Inch Subwoofer Sale Priced at $99.95 with Free Shipping. Sells for $198 at Amazon.

Warn the neighbors! This is serious bass from a top-notch speaker maker. The DXI1201 has a shipping weight of 25 lbs. and rocks a floor-pounding. According to Polk, it's equipped with a 12-inch Long Throw Driver and a 5-year warranty. Video games, movies, and music will all be substantially improved with this speaker. You can also place it wherever it's convenient, because bass is omnidirectional. More specs here on the Polk site.