This deal has ended.
Amazon.com offers this BIC America F12 12-Inch 475-Watt Front Firing Powered Subwoofer discounted from $499 to just $156.35 with free shipping. The next best total cost we could find was $196. This subwoofer has output capability of up to 116dB (live rock band levels). There is no sales tax (except KS, KY, ND, NY, WA).