Sonic Electronix offers the MB Quart 10" Dual ONYX Series Car Subwoofer, model no. ONX254SQ, for $44.99 with free shipping. That's tied with our Cyber Monday week mention and the lowest total price we could find by $6. This subwoofer handles up to 400 watts RMS (800 watts peak) and features 88dB sensitivity, frequency response of 35Hz to 150Hz, and more.