(a) An associate judge appointed under this subchapter is entitled to a salary in an amount equal to 90 percent of the salary paid to a district judge as set by the General Appropriations Act.
(b) The associate judge's salary shall be paid from:
(1) money available from the federal government;
(2) county money available for payment of officers' salaries, subject to the approval of the commissioners courts of the counties in which the associate judge serves; or
(3) a combination of money specified by Subdivisions (1) and (2).