Walmart offers the Blaupunkt 800-watt 12" Single Voice Coil Car Subwoofer for $24.99. Opt for in-store pickup to avoid the $5.99 shipping fee. That's the best price we could find by $13. (For further comparison, most retailers charge $49 or more). It features an RMS power output of 400 watts, peak output of 800 watts, and a 2" high-temperature aluminum voice coil.
The dollar store is the most amazing place to find bargains for certain purchases. Yes, even pregnancy tests.