Don't be a dick. Stop posting ignorance.
Equipment is as good or bad as the install that it is going into. You don't need to spend 1,000 dollars on a sub for it to sound good (hell even great).
Post away dude, and ignore anyone saying other wise. You are learning and came to the right place to get the information you need.
Many companies have come out with shallow mounts recently. The most anticipated (IMO) is the stereo integrity BM (someone mentioned the BM above but we are talking about different BM's i'm talking about the newest version). It won't be out till at least 1st quarter. If you need something soon, there are lots of subs. Let us know how much room you have available to you.
My recommendation for you would be a sealed shallow running between 350-500 watts. Check out the classified section for great deals.
I'm taking it you have a cd player already?
I'm not backing this website (i have never bought from them although I know people have with no problem)
http://www.woofersetc.com/index.cfm?fuseaction=category.display&category_ID=120&mfg_account_ID=&sort=account_name
But there are a bunch of different shallow mounts.