What is the ruling on a teacher taking money from students to decorate the teachers' lounge, or to compensate her for what she spent from her own money?

It is not permissible for a teacher to compel students to pay money for decorating the room, because the Prophet, peace and blessings be upon him, said: "The property of a Muslim is not lawful except with his willing consent." Also, the decoration of the teachers' room has no relation to the students. It is not permissible for her to compel them to pay for what she spent from her own pocket. It is permissible to take money from them only if she informs them of the true nature of how that money will be spent, and they willingly pay without reluctance, provided they are mature and discerning adults.