Newegg via eBay offers the NXG Technology 12" 500-watt Powered Subwoofer
in Black Pebble, model no. NX-BAS-500, for $174.99
with free shipping
. That's $5 under our mention from two weeks ago and the lowest total price we've seen. (It's a current low by $37.) It features an 18Hz to 120Hz frequency response and removable cloth grille.