O.C.G.A. § 36-91-51 (2019)

(a) In lieu of the bid bond provided for in Code Section 36-91-50, the governmental entity may accept a cashier’s check, certified check, or cash in the amount of not less than 5 percent of the total amount payable by the terms of the contract payable to and for the protection of the governmental entity for which the contract is to be awarded.

(b) When the amount of any bid bond required under this article does not exceed $750,000.00, the governmental entity may, in its sole discretion, accept an irrevocable letter of credit issued by a bank or savings and loan association, as defined in Code Section 7-1-4, in the amount of and in lieu of the bond otherwise required under Code Section 36-91-50.