Harman Kardon offers its factory-refurbished Infinity by Harman Kappa Five 5-Channel Amplifier for $144 with free shipping. That's the lowest total price we could find for a new model by $125. It features 50 watts RMS into four channels and 350 watts RMS into one channel, 85dBA signal-to-noise ratio, 12dB per octave electronic crossover, and frequency response of 10Hz to 75kHz. A 3-year Harman Kardon warranty applies.