Hi, I've looked up this bug, and if it has already been posted just delete this thread.
There are several different kinds of trinket from the horde field scout, all doing different things.
These are called Mark of Conquest, this restores health on melee hit and mana on range hit (Warrior, Hunter, Rogue).
Mark of defiance restores mana on spell hit (Priest, Mage, Warlock).
Mark of vindication restores mana on melee hit (Paladin, Shaman).
This bug requires you to be Horde, and atleast level 62.
1. Get a mark of conquest from the Horde field scout in Zabra'jin, Zangermarsh. http://thottbot.com/c18564/z3521/b
2. Get another trinket, any other one, it doesn't matter.
3. Swap which slot your trinkets are in, e.g TrinkSlotOne>TrinkSlotTwo>TrinkSlotOne etc etc.
4. Repeat step three ATLEAST 30 times.
5. Start hitting, and never run out of mana/health.
If you are a warrior/rogue This basically makes you invincible. Since the more you switch it, the more health you get. From one proc it can give like 2k health. Normally it would only give 100.
If you are a mage/pally/hunter/shaman/warlock/priest, you never run out of mana. This isn't as good as the health one, but it's still really handy. Enjoy.
Also Credits to Masonboy345 for showing me how to weapon stack, and mentioning that you could use trinkets to trinket stack in his video.
Masonboy's video on how to weapon stack: [ame="http://www.youtube.com/watch?v=riVIZOUk9ec"]YouTube - weapon stacking for mmowned![/ame]
EDIT: Just realized that some servers won't sell them for free, most ones with a mall with auto sell it free. e.g wowtrance, aniwow, wowmmo. IF they do not sell it free, then you need to get the marks, which is a pain.