Newegg offers the Polk Audio 5.1-Channel Home Theater Speaker System, model no. RM6750, for $159.99. Apply coupon code "VCOBF15" and pay with Visa Checkout to drop it to $149.99. With free shipping, that's the lowest total price we could find by $70. It comes with a center-channel speaker and four satellite speakers with 3.25" cone drivers and 1/2" tweeters, plus an 8" 50-watt powered subwoofer.
Note: The coupon can only be used once per account.