Monoprice offers its Monoprice Premium 5.1-Channel Home Theater Speaker System, model no. 13773, for $139.99 with free shipping. That's $60 off list and the lowest total price we could find. The four satellite and the center channel speakers each feature a 3" paper cone woofer and 90Hz to 20kHz frequency response; the powered subwoofer features an 8" forward-firing speaker, 40Hz to 1.3kHz frequency response, and 200-watt amplifier.