I plan to run a similar setup for my office. I've spent countless hours looking and researching for some older quality gear that I can use for an inexpensive office system. My conclusion is that an older HT receiver is really quite a value when you consider that it will have a tuner, DAC, preamp, and amp. Another handy feature of a HT receiver that might be helpful is the built in crossover, usually at 80hz. I would think you should be able to find a variety of older quality HT receivers for $350 or less.
I believe Music Hall made a two channel receiver that included a built in DAC but it also will most likely be beyond your budget as well.
If you already have a decent receiver and speakers, then I think purchasing a DAC is a good idea. The Musical Fidelity V-Dac is a popular one that comes to mind that is within your budget although I've never heard it. I have a Monarchy Audio M22 that I really like but it might be a little beyond your stated budget.
I believe Music Hall made a two channel receiver that included a built in DAC but it also will most likely be beyond your budget as well.
If you already have a decent receiver and speakers, then I think purchasing a DAC is a good idea. The Musical Fidelity V-Dac is a popular one that comes to mind that is within your budget although I've never heard it. I have a Monarchy Audio M22 that I really like but it might be a little beyond your stated budget.