(a) Except as provided by Subsection (b), the board may prescribe the method of making purchases and expenditures by and for the district.
(b) To the extent competitive bidding procedures in Title 8 apply, the board may not enter into a purchasing contract for more than $15,000 unless the board complies with Chapter 252.
(c) If the municipality that created the district has a purchasing agent authorized by law, that agent shall serve as purchasing agent for the district.