Price is everything here. What is the cheapest subwoofer (or maybe brand) you know of. It'll be pairing up with 3 Acoustic Research speakers from the HC4 system (It's a long story where the other 2 speakers and included subwoofer went to). This sub will be used mostly by my mom (no, I'm not a 40 year old living in his parents' basement

...I'm 16.) on the treadmill and she wants some bass. My mom isn't an audioholic whatsoever so the sub doesn't need to play unbelievalbe lows. Thanks for any recommendations!