Is it permissible, Islamically, to conceal the purchase of a Qur’an with money designated for job searching, and to tell one’s father that it was spent on food and drink, even if the father approved of that expenditure?

If the father permits spending money only on food and drink, then it is not permissible to exceed his permission, due to the Prophet's (peace be upon him) saying: "Muslims are bound by their conditions." Likewise, it is not permissible to lie by saying that the money was spent on food and drink while you bought a Mus'haf with it.