I have some (8" woofers) in wall speakers, which produce mostly treble. I use a 'medium' subwoofer to provide low range but also frequencies a bit higher than just sub sonic, to fill the void that the in walls can't produce. I'm not after earthquake styles (been there

My cheap as$ kenwood alien head woofer just died, even after I fished the kids toys out of it. I'm looking for something to replace this and just wondering if anyone had anything they're not needing any more.
Trademe has some Sony 12" jobs for around $100 so I might keep an eye on those. I know what's nice, and then I know what I can afford, so mostly just after something that can extend the in walls down a bit, but not to the pits of hell sort of thing.
Any ideas?
Cheers.