The currency used in wow is called World of Warcraft gold, or wow gold. People who do not want to spend too much time leveling and making gold can simply purchase cheap wow gold from a virtual currency shop such as this site. Accounts are also bought and sold quite commonly. The process of leveling can be quite dull, and many people would rather pay real money in order to enjoy the game more. Accounts can sell for quite a lot of money.
World of Warcraft is a very fun game, that provides seemingly endless entertainment. You need to buy wow gold. However, be warned; wow is incredibly addicting. If you are considering playing World of Warcraft, just know that you will probably become addicted to it. There is literally thousands of hours of potential game play. I personally know many people who play wow as much as humanly possible.
For those who enjoy fighting enemies, raiding is not the only option. There is also Player vs. Player (PVP) servers, where you can fight fellow gamers for fun. These servers allow you to combat other players, without organizing a raid. These fights are purely for fun, although, for competitive people there is a rank system, in which you gain popularity by defeating others.
There is really nothing to gain through PVP and raids, except a small amount of experience. PVP and raids are usually done for fun. Unlike many games, you do not loose anything when you die. When you die, you simply have to walk back to your body, and pick up your items. You cannot loose items or gold, so there is no need to fear dying.
So before you pick up wow, know that you are at risk. Even strong willed individuals have trouble quitting wow. Personally, I put on a few pounds, but in my opinion the trade off was worth it!