Best Buy offers the Insignia Rocketboost 6.5" 70W Wired / Wireless-Ready Subwoofer
, model no. NS-RSW211, for $19.99
with free shipping
. That's $70 off list and tied with our August mention as the lowest total price we've seen for any standalone subwoofer. Sales tax is added where applicable. This 70-watt subwoofer features a 6.5" speaker, line-in audio input, and is Rocketboost RF-RBUSB wireless signal compatible.