Section 13. An authority and all its real and personal property shall be exempt from taxation and from betterments and special assessments; and an authority shall not be required to pay any tax, excise or assessment to or for the commonwealth or any of its political subdivisions; nor shall an authority be required to pay any fee or charge for any permit or license issued to it by the commonwealth, by any department, board or officer thereof, or by any political subdivision of the commonwealth, or by any department, board or officer of such political subdivision. Bonds and notes issued by an authority, their transfer and the income therefrom, including any profit made on the sale thereof, shall at all times be free from taxation within the commonwealth.