Walmart offers the Blaupunkt 300-watt 8" Amplified Car Subwoofer for $59.99 with free shipping. That's $9 under last week's mention and tied with the lowest price we've seen. (It's the best deal now by $37.) It features variable bass boost up to +18dB, variable input gain control, and thermal short and overload protection.
The dollar store is the most amazing place to find bargains for certain purchases. Yes, even pregnancy tests.