The worst snake oil is not where some device, like cryo-treated cable, is sold with extravagant claims about improved sound. It's the snake oil that wastes much more of the buyer's money.
It's the idea that 2-channel stereo receivers or amps have inherently better sound quality than modern AVRs. People who buy into this usually start off objecting to the cost of unused amplifier channels, not to mention all those other unwanted features. They claim they only want the best sound quality for music. Sooner or later, the salesman talks them into two different systems, one for music and one for movies. It costs them much, much more than any of those dubious gimmicky devices.
