As one of its daily deals, Best Buy offers the Polk Audio 12" Car Subwoofer, model no. DXI1240DVC, for $49.99 with free shipping. That's the lowest total price we could find by $50. Features include a 20 to 300Hz frequency response, dual 2" 4-ohm KSV voice coils, and power handling up to 360 watts RMS (720 watts peak). Deal ends today.