If you're willing to do a little bit of DIY you could make this happen. All you would need is a cheap jig saw
(or just grab the cheapest one at walmart).Assembled and finished sub cabinet10" sub driver100 watt plate amp
All you need is a pencil compass, and a ruler. Place a 9" circle on the front baffle, and a 6.5"x7.5" square on the rear baffle. Drill a hole big enough for the jig saw blade, and cut the material out. Now all you need is gasket foam found at any home improvement store to go around the driver, and screws to install it (and the amp). Grab a cheap poly-filled pillow from walmart/target and throw it in the box, connect regular wire from the amp to the woofer and you're done.
-3db is 40hz anechoic, shown with 100 watts input and 80hz high pass filter. If the room is small the low end will be lifted flat.