hifisandwich wroteThe trouble is that the DAC I fancy (the TDA1543 DAC featured here) seems to be $120 on its own so I don't think I can package the whole lot up in just $100 unless I am misunderstanding something. I am in the UK
Oh...
Yes, some DACs are expensive

You can also build your raspbery pi system, then chose which software you want to run on it. Either a squeezebox based system or Rune will be fine. (and you can ditch your SBT

)