rotipom,

Try not to get the cheapest one as you'll find yourself wanting to upgrade before long, most of those cheap subs from BestBuy or CircuitCity are boomy and far from being musical, wait for a little while till you saved up enough money then get a good one, such as the SVS PB10 for around $420. If you have to have a sub now, and $200~300 for a musical sub, you can either get used one from audiogon, or jump on the PartsExpress's sealed 10" Titanic MKIII.