Anything to make it easier to level in World of Warcraft gets a thumbs up from me no matter what. The World of Warcraft Quest Helper is a free game add-on that helps you level by pointing an arrow telling you the closest location of things to kill for quests you have, where items are and where to find NPC's.
There's only a handful of these Wow Quest Helper add-ons available to help you level faster. There's a Free one called "Quest Helper", the problem is, it wasn't written by a professional gamer. This means the paths or routes for questing aren't the most efficient, meaning you won't level as fast as with some other Quest Helper add-ons.
In fact, the first add-on I used was the Free WoW Quest Helper add-on. I soon realized sometimes it would tell me to do something, and I knew it wasn't the most efficient because sometimes it would tell me to fly somewhere when I knew there was closer quests or a chain quest to complete for a great blue or green quest reward.
Also, there are many people who complain because the Free Quest Helper add-on can be a memory hog. If you don't have a high end gaming machine you might notice it can slow down your game quite a bit and cause the game to become "jumpy."
The Free Quest add-on also didn't include an in game guide, yes, it points an arrow to where to go, but it doesn't give any other quest details like the more advanced add-ons.