How "good" are we talking? I got some nice speakers for like $25 at a computer show awhile back. They're fairly large for simple stereo speakers; they include a main speaker, and a tweeter in a single package...well, a pair of them. 🙂
They were rated "460Watts" which may or may not be accurate. These were Nicole brand or something like that; bass and treble controls.
Check out eBay's speaker selection; they got lots of types there.