What kinds of things are sold by characters in your game that wouldn't normally make it to a PC's character sheet?

In our non-magical world you can buy invisibility talismans, magical disease cures, haunted dolls, pills that empower the Brownian (random) motion of gasoline molecules to make it more efficient, and other magical paraphernalia.

Surely someone in the Sixth World is selling a real (probably not actually working) Hand of Glory to would-be thieves, or other mythological items that might or might not do anything. Cold Iron has probably made a comeback with the belief-powered magic with belief-powered geasa and weaknesses/allergies. Silver bullets work, and are probably produced a dozen different ways for different specific effects that may be mostly salesmanship (mine are cast six hours prior to moonrise of a full moon for maximum effect!). Crime Mall, market stalls, and the Matrix should be full of this stuff.

What has showed up in your games? What actually works and to what degree? What is just snake oil?

For my very short lived HK campaign, I had ruled that magic trinkets could work (especially those made of real jade) but it was not necessarily possible to tell it by looking at it in the astral plane.
In my head the concept was to have them work only in some circumstances and preferably only have impact on the GM rolls so that the players could never be sure if trinkets were really working or not.

The most interesting thing we run into (in our campaigns in Asia) is the natural remedy known as Tiger Ball...

Makes you faster, stronger, cures all ills, purifies the body, etc. Kind of like the Snake Oil Remedies of The Wild West, but with real "Magic".
Tiger Ball works similar to what Blade describes above.

It is entertaining.