Prior to the issuance of a certificate of occupancy by the building official no transfer of the property or any interest therein, except a transfer to a bona fide mortgagee or similar lienholder, may be made by the homesteader without the approval of the urban homesteading agency, provided any such transfer may only be made for a consideration not in excess of the cost of the property to the homesteader together with the costs of any improvements made or construction thereon by the homesteader.