All work and purchases of supplies, materials and services of less than the estimated value of ten thousand dollars ($10,000.00), unless otherwise required by two-thirds vote of the aldermen holding office on the city council, shall be made in the open market, without newspaper advertisement and without observing the procedure prescribed by this chapter for the awarding of formal contracts requiring competitive bids. Further, by duly enacted ordinance of the city council, the city council may authorize city officers and/or city department heads to make open market purchases of material, equipment, supplies and services not involved in public works projects and by such ordinance establish the limit or amount of the expenditures so authorized. (Ord. 977 § 1 (part), 1992: prior code § 2-4-8(J))