Before any revenue bonds or certificates, excepting refunding bonds or certificates, are sold pursuant to section 18-815, the entire authorized issue, or any part thereof, shall be offered for sale as a unit after advertising for bids at least three times in a legal newspaper in or of general circulation in the municipality or municipalities served by the regional metropolitan transit authority, the last publication to be at least ten days before bids are required to be filed. Copies of such advertisement may also be published in any newspaper or financial publication in the United States. All bids shall be sealed, filed, and opened as provided by resolution adopted by the board, and the revenue bonds or certificates shall be awarded to the highest and best bidder or bidders therefor. The authority shall have the right to reject all bids and readvertise for bids in the manner provided for in the initial advertisement. If no bids are received, such revenue bonds or certificates may be sold at the best possible price according to the discretion of the board, without further advertising, and within thirty days after the bids are required to be filed pursuant to any advertisement.