I am using a Majik Bus, sold by PI Audio Group. They have a Circle here in the vendor section.
It does a great job of filtering the AC. The background is quieter, which allows more detail, better bass, soundstage, to come though. Its a great improvement. It has 4 outlets so I am able to make 3 additional components sound better.
The Makik Bus is slightly out of your price range, and I don't have any under $200 suggestions. Hopefully other can provide a viable suggestion for you.