KRS 97.690

All work to be done or supplies or materials to be purchased involving an expenditure of five hundred dollars ($500) or more shall be awarded by contract to the lowest and best bidder, but the commission may reject any bid. The commission may do any part of the work, under such conditions as it prescribes, by day labor or other noncontract method, whenever, in its judgment, this is the best method to pursue. This section does not limit the power of the commission in the employment of architects, employees, clerks or agents.