Now, if you are having trouble getting to exalted with your guild like I am, put on your Tabard and do every trick or treat quest there is. I'm currently getting 42 rep per "Pumpkin" quest. I have not bothered to add the total amount possible (also for lesser levels I'm sure a ton of experience and gold.) Also if you have trouble finding an Inn, follow the pumpkins, they lead you right to them. Go down the list, check em off, get your achieves, rep, experience and gold and enjoy the best holiday in WoW:)
Those candies you get from trick-or-treating have changed several times over WoW's history. They used to be buffs, offering amounts of stacking stats such as spell power with every consumption. However, that's changed and they now provide only visual effects.
WoW: Trick or Treat Achievement in the old Blasted Lands zone ..
It is looted, a quest reward and sold by NPCs
In the Other Consumables category