How much is a good budget to spend on new clothes for work at a law firm?

The best budget would be zero. Do not spend any money. You don't know how well they are going to treat you. So wait to buy clothes until you have profits from the new job. Borrow clothes if you have to. No one will care. All that matters is your smile. Everyone who comes to a law firm has troubles in their own lives. They don't even look at you and won't remember you 2 minutes after they are gone. Not because you are not nice; but because their minds are full..