Originally posted by moofoo
:slap: dont scare him by saying stupid crap like that...
bro lemme set you up with a nice sounding sub system that wont break your bank account and with sound you will love. 
(A) Sub enclosure... subzone 0.85 12inch box around $65 thezeb.com
(B) Amp: us acoustics 2 channel USX2150 400watts bridged $160 thezeb.com
(C) Sub: elemental design 12 inch e12K about $135
edesignaudio.com
Install you have about $140 left for installation shop around for shops and compare install prices (labor plus amp kit & wires)
Sub,amp and box = around $360.
I myself have a E12K with a JL Audio 250/1 watt mono amp with a subzone 1.2 cube enclosure... the sound is very very nice.
Hope this helped ...
I'm not trying to scare anyone away, try reading his post, it helps.
What he wanted according to his post is 'some' subs which refers to more than 1. Pull that off for less than 500 and don't underpower those subs.
Granted you could probably do it for under $1000, but for $500? I doubt that. Unless he only wants one sub.
-Diabolik