i think he was kidding around!!
there are a few econo-subs avail if you need to save a few bucks.
the 10" dayton sub from parts express is decent sub for around $150 bucks.. and the vega subs, the LW-10, and the LW-12 are pretty good at around $160-$200. keep in mind, these subs do not have the ultra low extension as the much better HSU, SVS, and AXIOM subs, but they will do in a pinch. i have the vega LW-12, and it has plenty of low end bass, but can be boomy at times.
it comes down to quality-vs-price.. the choice is yours!!
EDIT- peter, your son keeps lookin at me!!!
bigjohn