(a) Each specific improvement and each purchase of supplies, equipment or materials the expenditure for which exceeds an amount set by ordinance, as provided for in Section 67(b) hereof, shall be done by contract authorized by resolution of the Council and said contract shall be let to the lowest responsible bidder after advertising for sealed proposals for five (5) consecutive days as required by this Charter. Such notice shall give a brief description of the work to be done or the supplies, equipment or materials to be purchased. The Council may reject any and all bids. If all bids are so rejected or if no bids are received, the Council may readvertise for new bids, or authorize the City Manager to negotiate in the open market for a contract at a reasonable price, or authorize the City Manager to purchase in the open market, or authorize the City Manager to have the work performed by City employees.

(b) The ordinance establishing the amount for which each specific improvement or purchase shall be approved by the City Council shall not be adopted or amended except upon a 6/9 vote of the City Council.