Counties may participate in nationwide purchasing programs sponsored by the national association representing counties, and local cooperative procurement agreements entered into by the counties and other local jurisdictions or any other competitively bid nationwide purchasing program.
19 O.S. § 1501(A)(3)(p)

A purchasing program is defined as an association of public entities working together to provide leverage in achieving the best value and/or best terms in contracts awarded through a competitive bidding process that would be purchased under the normal guidelines of Title 19 of the Oklahoma Statutes.

Cooperatives may not be used when purchases are under Title 61- Public Competitive Bidding. This is normally related to buildings. Refer to Chapter Five, “Public Competitive Bidding Act.”

For these purchases, the contract shall be attached to the Requisition - Purchase Order - Claim, and normal purchasing procedures shall be followed as outlined in Chapter Four, “Purchasing Methods and Procedures.”