Originally Posted by
dryankem
Just try the 10 free trial and you can be any race and any class (well not 100% sure about monk but pretty much anything).
When/if you buy WOW, you don't need to buy everything at once. You can buy the battle chest which comes with vanilla, bc & wrath and play up to level 80 before needing to buy Cata and finally MOP (but as stated above me you do need each expansion before MOP to play MOP).
If you aren't sure about the game, try the trial and then try the battle chest for a couple months and by that time you should know if the game is for you or not.