Sec. 4.13. CONTRACTS FOR PURCHASE OF VEHICLES, EQUIPMENT, AND SUPPLIES OVER $15,000. (a) If the estimated amount of a proposed contract for the purchase of vehicles, equipment, or supplies is more than $15,000, the board shall ask for competitive bids as provided by Section 4.07 of this Act.

(b) This section does not apply to purchase of property from public agencies or to contracts for personal or professional services.