Thought I would share some good deals.

Probably should know I am not in any way affiliated with these sites, although I am a member of the acoustic vision's sister forum, soundillusions.net (Thats how I got here)

These daytons are good subs, 15.1mm (1 way) Xmax!)

Dayton 12" DVC $100 Shipped

Dayton 15" DVC $116 shipped

Here are some unbranded Kove Armageddon Zs. Although they arent really unbranded cause mine sure as heck isn't:
My Parts Express "Unbranded" Z-15D

12" Kove Armageddon Z

This is the one I got, the pictures dont do it justice, it is massive. The biggest sub I have ever installed. It weighs about 35 pounds and burped 151dB in an explorer, ported box, with 1800W if my memory serves me correctly. It is an SPL sub.

Kove Armageddon Z15D

Here are a few more pics of it:
http://www.twinjy.com/images/kove1.jpg
http://www.twinjy.com/images/kove2.jpg
http://www.twinjy.com/images/kove3.jpg