The city manager, subject to regulations prescribed by the council, may contract for the lease or sale of real or personal property, or any interest therein, owned by the city after having complied with the laws of the state of Oklahoma and the city of Purcell related to declaring said property obsolete. Every contract for the sale of any property, or any interest therein, exceeding an amount to be established by resolution, shall require the prior approval of the council and shall be by competitive bid. The city manager may reject any and all bids.