Groupon offers the West Coast Customs 2,000-watt Car Amplifier, model no. WCC2200.5, for $144.99 with free shipping. That's the lowest total price we could find by $55. It features three sets of RCA inputs, four A/B channels, and one 1,000-watt subwoofer channel.

Also available is the West Coast Customs 1,600-watt Car Amplifier, model no. WCC1600.4, for $114.99 with free shipping. That's the lowest total price we could find by $35. It features four bridgeable channels and a continually variable crossover.