P.C. Richard & Son offers the Polk 8" 70-watt Wireless Powered Subwoofer, model no. PSWi-8M, for $149.99. With free shipping, that's the lowest total price we could find by $10. (Most merchants charge $200 or more.) This 8" subwoofer features a built-in 35-watt (70-watt peak) amplifier, frequency response of 42Hz to 120Hz, 2.4GHz wireless transmitter, USB connectivity, and more.