It seems like you're looking for more than just a DAC. Is that right? If so, I'd recommend a Raspberry Pi. It doesn't get much cheaper, and you can control it from a phone. Also they're small enough, and use so little power, that you could just leave it on 24/7.
Are you looking for something that can hook up to your stereo and play music that's stored on a computer, over your home wireless network?