Each authority shall establish a fund to be designated as the "transportation fund", in which shall be placed all sums received by the authority from any source, and out of which shall be expended all sums disbursed by the authority. The county treasurer shall be the custodian of the fund, and the county auditor shall keep the record of the receipts and disbursements, and shall draw and the county treasurer shall honor and pay all warrants, which shall be approved before issuance and payment as directed by the authority.

The county and each city or town which is included in the authority shall contribute such sums towards the expense for maintaining and operating the authority as shall be agreed upon between them.