Is it permissible to pay Zakat on money for study expenses, books, or school transportation?

Zakat is not obligatory on saved money unless it reaches the nisab (minimum threshold) by itself or when combined with other assets, and a hawl (full lunar year) has passed on it. It is permissible to assign a separate hawl for each installment or a single hawl for all of it. The default is to pay zakat in cash to those who are eligible. It is not permissible to give it in kind (as goods) unless there is a strong overriding benefit, with emphasis on delivering it to those who are eligible.