The SVS PB10 and Epik Legend are $500, but shipping puts them over that. Both are supposed to be very good. The Elemental Designs A3-250 is kind of a PB10 clone, and is only $450 shipped, that should be a good sub too. If you have some elasticity in your budget, look at the Elemental Designs A3-300, the Hsu VTF2, or the Outlaw Audio LFM-1 Plus, although they are all 600 shipped, but they would be a step up from the $500 subs. You will get your moneys worth with any of these, so there are no wrong choices here.