Did a quick search on ebay.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7917374890&category=38647

Here's little 8" Kicker sub for $50 shipped. Someone will correct me if I'm wrong, but I believe this sub can be free-air mounted (rear deck).

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=48598&item=5716380921&rd=1

Here's a kicker amp for $97.50 shipped. Says 120x1 RMS, should do an ok job pushing the 8.

Not too bad for $147.50. I'm sure you could do even better with a little more searching around on Ebay.

~~~~~~Mike~~~~~~ Black 2006 VW Rabbit Silver 2000 Contour SVT - SOLD ~~~~The Car~~~~~