All costs incident to the publication of the aforesaid notices and all other costs incident to the public hearing and election hereunder shall be borne by the parties filing the petition; and the board or boards of supervisors, in its or their discretion, may require the execution by the parties filing the petition of a cost bond in an amount and with good sureties to guarantee the payment of such costs. However, the board of supervisors may, in its discretion, pay the costs of the hearing and election, or such portion as it deems proper, if it considers the proposal to be of sufficient public interest.