Why do you need that?
Why do you need that?
Why should you do that?
Why do we need that for?
Why do you want to do that?
What do you need the money for?
What do you need this money for?
Why does Tom need that?
Why don't you do that?
What do you want so much money for?
Why do you have to do such things?
Also, why do you want to do so?