No county, city, town, taxing district or other municipality shall be authorized or permitted to grant any franchise or privilege, or make any contract in reference thereto, for a term exceeding twenty years. Before granting such franchise or privilege for a term of years, such municipality shall first, after due advertisement, receive bids therefor publicly, and award the same to the highest and best bidder; but it shall have the right to reject any or all bids. This section shall not apply to a trunk railway.