ok iam going to get cataclysm but i only have WoW and burning crusade.

I have burning crusade and the first wow can i buy cata some people say i can but you dont get all the content

I think you need the previous Wrath of the Lich King expansion pack too, because you need that to level up to 80.

It says on the cover that you need to install WOTLK.

Yep.. I knew I should've bought WotLK when it was $10 a week ago. I was hoping to buy Wrath only when I had gotten close to the level cap, but you can't even apply the Cataclysm key to an account that doesn't have all the expansions.

you need Wrath, but, rejoice, as it is only 5 dollars via Blizzard store!