bazooka sub
Mike if you are going to do this plan the system from the inside out. If you are needing a Cd Player, amp, woofer and wiring(matter of fact this is the MOST important part of your system hands down your system is only as good as the wiring and install). Are you looking for good rythem to the music thump or window rattleing, door shaking thump? Stay away from Wal-Mart (they stock alot of B Stock units). Shop your local craigslist for deals of things BUT MAKE DAMN SURE IT WORKS BEFORE YOU BUY. The more power and watts you run the more expensive the wiring gets. Also when shoping for a sub dont just look at the WATTS rating. Look for the OHM rating, Sensitivity, and xmax. Remember once you have your sub bought now buy your amp. Make sure the amp you buy does the OHM load rating you need this based on the subwoofer and how you wire them and puts out atleast half the rated power of the sub in RMS not Peak. You have just as good of a chance to blow a sub if you underpower it. There are a handful of companies to stay away from just shop ebay you will see most of them.
Figure $100-150 for a nice CD Player (If you cant get one used or free)
$50-100 per sub for a decent one not a junk brand.
$150+ for a good amp (Could be had for less if you shop smart)
$50 atleast in wiring, connectors, fuse links/blocks.
Enclosure is Important. A good TUNED box is worth its weight in gold. Figure this on what kind of music you listen to. Ported and sealed are the options but taylor it to your music of choice.
I have several calculators that make box building EASY right down to the lenght of each cut you need and how to assemble. Make it out of atleast 3/4 MDF about $20 per 4x8 sheet. xx
Any questions to installs or what to or what not to buy PM me Id be happy to help