The members of the board of park commissioners are entitled to receive compensation for their services in the amount approved by the board in the park district annual budget. A park board member may not be directly or indirectly interested in any contract requiring the expenditure of park district funds unless the contract has been approved by two-thirds of the park board. Before the contract is approved, a motion must be made and approved that the service or property is not readily available elsewhere at equal cost. Regardless of this section, any park board, by resolution duly adopted, may contract with park board members for minor supplies or incidental expenses.