Amazon offers the Logitech Z506 5.1-Channel Surround Sound Speaker System
, model no. 980-000430, for $49.99
with free shipping
. That's tied with our mention from last winter as the lowest total price we've seen for a new unit. (It's also a current low by $20.) Features include 75 watts RMS, down-firing subwoofer, 45Hz to 20kHz frequency response, and 3.5mm audio input.