If you hurry Elemental Designs is having a great group buy currently that ends on 6/13. All you have to do is sign up as a member of their forum to receive the discount. I think you'll be hard pressed to find a better speaker in your price range. A 13Kv.2 for $75+ shipping looks like your best bet (its a 12" sub, their naming system is kinda silly).
http://www.icixsound.com/vb/showthread.php?t=26191 
