I use pure Silver in all my system, including a couple of power cords. The result will greatly depend on the design of the cables. The experience I have with Dynamique Audio is excellent. I'm using their cables for the last 5 years and have been moving up in the chain to get to the Apex line. Their top cables are the "no cables". Their goal is to achieve the maximum in neutrality and tonal balance. What you'll hear is the result of your components sound signature only. You can find many great reviews online. Regarding digital cables. The Apex is out of your budget, but "The Cable Company" represents them in the US and they have the other cables as well. The BNC cable I traded in for the Apex digital is still listed in their used cables website and you could give it a try (https://www.usedcable.com/dynamique_audio.html).
Good luck with your search.