Sonic Electronix offers the RE Audio SE-X Series Dual 15" Car Subwoofer
, model no. SEX15D4, for $136.95
with free shipping
. That's the lowest total price we could find by $22. It handles up to 600 watts RMS and features a 3" 4-layer voice coil, triple stacked magnets, and Tork-Tite terminals.