Hi Swidez,
I am not familiar with that model, but I know that you can buy some Cerwin Vega subwoofers for only $20. It's not a great brand for a sub. You'll be better off to look at better companies for a used sub, and also perhaps increase your budget a little more. Good places to shop for used audio equipment, speakers, subs, etc., is Audiogon and Videogon. It is very tricky to buy from e-bay, or places like that in general.
For used subs, look for brands like; Atlantic Technology, Axiom Audio, Boston Acoustics, Definitive Technology, Energy, HSU Research, Jamo, JBL, Kef, Klipsch, Monitor Audio, Outlaw Audio, Paradigm, Polk Audio, PSB, RBH Sound, REL, Velodyne, and even Yamaha.
Cerwin Vega is simply not the best sub around. All the other ones, from just above, are better in my opinion, I'm sure of that (100% sure).
Cheers,
Bob