Tennessee Code Title 6. Cities and Towns § 6-19-104

(a) The city manager shall be responsible for all city purchasing, but the city manager may delegate the duty to make purchases to any subordinate appointed by the city manager.

(b) Competitive prices for all purchases and public improvements shall be obtained whenever practicable and in accordance with regulations established by ordinance, and the purchase made from or the contract awarded to the lowest and best bidder; provided, that the city may reject any and all bids.

(c) Formal sealed bids shall be obtained in all transactions involving the expenditure of an amount to be set by ordinance. The amount set shall be equal to or greater than the amount set in chapter 56, part 3 of this title, but may not be greater than twenty-five thousand dollars ($25,000). The transaction shall be evidenced by written contract when necessary. In cases where the board indicates by unanimous resolution of those present at the meeting, based upon the written recommendation of the manager, that it is clearly to the advantage of the city not to contract with competitive bidding, it may authorize noncompetitive contracts.

(d) The city manager may reject all bids and authorize the making of public improvements or accomplishment of any other city work by any city department.

(e) Purchasing and contract procedures not prescribed by this charter or other law may be established by ordinance.

(f) The board of commissioners may by ordinance delegate to the city manager the authority to enter into binding contracts on behalf of the city, without specific board approval, in routine matters and matters having insubstantial long-term consequences. The ordinance shall enumerate the types of matters to which the city manager's authority extends and may place other limitations on the city manager's authority under this subsection (f). As used in this subsection (f), “routine matters and matters having insubstantial long-term consequences” means any contract for which expenditures during the fiscal year will be less than twenty-five thousand dollars ($25,000).