You don't need money to play WoW!!
I run on a modified realmlist that connects to a private server called Middle Earth and you just go to their page, login and play.
however it is still in the Burning Crusade era at patch 2.4.3, but you can find others, like toxic WoW at 3.0.3
Just do some hunting around, the hardest part is getting the game, its so big
I just got the DVD's from a friend...and you can always get the base client and patch your way up.