It just acts as an mp3 player, point it to a directory on the computer with the music in and it will only play what is in that directory.

You'll struggle to find the new SB3 for under £229, but you could try looking for an SB2 on ebay (they are the same hardware inside), I imagine a few will be appearing from people buying the new model.

If you need a PC to act as a music server, I have put details of an easy to use, pre-configured server in the trade adverts, I have also just managed to get some tiny pc's for those after a smaller solution.

Andrew