(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 purchasing contracts that involve spending more than $25,000 unless the board complies with:
(1) Subchapter C, Chapter 262, if the district was created by a county; or
(2) Chapter 252, if the district was created by a municipality.

(c) If the political subdivision that created the district has a purchasing agent authorized by law, that agent shall serve as purchasing agent for the district.