I can get you a brand new SA-15 for $250 shipped with a 2 year warranty.
But I have to throw you some advice...I'm not bashing you, or hating on you, you seem cool to me.
Dude you are all over the place with the subs...Once you get a little more mature you will learn to save up money for the correct gear, not just impulsively buy the cheapest things you can find.
Instant gratification will almost always get you ripped off.
Just some words of wisdom from a fellow Michigan member. I wish you good luck with your system.