During that period of the calendar year not embraced within the regular school term to provide and conduct courses in subject matters normally embraced in the program of the schools during the regular school term, to fix and collect a charge for attendance at such courses in an amount not to exceed the per capita cost of the operation thereof, except that the board may waive all or part of such charges if it determines that the family of an individual pupil is indigent or that the educational needs of the pupil require his attendance at such courses, and to give regular school credit for satisfactory completion by the student of such courses as may be approved for credit by the State Board of Education.