Any true 5.1/7.1 headphones in the sub $100 range won't be of high quality.
I myself use the Sharkoon X-Tactic 5.1 Digital headphones (which are just the X-Tactic Analog with a Dolby Digital decoder box). My current pair is getting a bit worn and I'm seriously considering purchasing the newer X-Tactic Pro.
I highly advise against purchasing any headphones that use USB, especially surround headphones. The best ones use 3.5mm jacks and require an actual sound card.