Section 20. The school committee shall, two weeks next before the opening of each term of the evening schools, post in three or more public places in the town notice of the situation of said schools, the date of the beginning of the term, the evenings of the week on which they will be in session, such regulations as to attendance as it deems proper, and the provisions of section ninety-five of chapter one hundred and forty-nine. Except in the city of Boston, the school committee may require from each student, not bound by law to attend, an advance payment not exceeding twenty-five dollars for each course offered for which the student registers and for which the town receives no reimbursement from the commonwealth or any of its agents, and not exceeding twenty dollars for each course offered for which the student registers and for which the town is reimbursed in whole or in part by the commonwealth or any of its agents, which fee may, at its discretion, be paid into the town treasury to be credited to the school appropriation, or be returned in whole or in part at such time and under such conditions as the committee determines. In the city of Boston, the school committee may require from each student, not bound by law to attend, an advance payment not exceeding five dollars, which may, at its discretion, be paid into the city treasury to be credited to the school appropriation, or be returned in whole or in part at such time and under such conditions as the committee determines.