Consult the Municipal Bureau of Culture or the Propaganda Department first. Municipal competitions are generally sponsored or co-organized by cultural centers or cultural bureaus, literary federations or propaganda departments. You should go to these units first and present your detailed plan to the relevant person in charge. If it is self-funded, the government department should be happy to approve it.
The specific expenses include venue rent, utilities, competition paper and ink, staff salaries, publicity expenses, etc.