I don't see how it could be done for $200, no way, no how.
The bare modules cost $175 from TPA, add a trafo and you're now at $197 + shipping. And that's with no connectors, no wire, no chassis, etc. So I'd estimate that you're looking at ~$300 for just the parts for a SPDIF only Opus, probably more. If you want USB add another $75 in parts, same thing for the Ballsie. $200 is impossible.