Well maybe a 100$ for a pair.
A simple 2.1 speaker system do a good job. Surround sound are just a gimmick to make you spend more on a few added sound effect that are not available in all movies.
Beside I did have a home theater system 5.1 and I have play movies in it, but the surround is not really there.
Since its mostly for music, I need good sound. Place are limited and I can't play loud. Also a plug for headphone on it would be great since the tower is too far to connect the headphone on it.