The purpose of grants-in-aid shall be: (a) To encourage the development of local community initiative in broadening the scope of noninstitutional care and training programs for people with intellectual or other disabilities; (b) to maintain minimum standards for the operations of such programs; (c) to review the experience of individual programs as they develop; and (d) to foster the progress of day care programs to successively higher levels of quality and service. Grants-in-aid under the provisions of this act shall only supplement local funds, shall not exceed one-half of the cost of operating expenses of day care centers for children with intellectual or other disabilities and shall not be used for the purchase or construction of buildings.