A “Business” is classified as the carrying on or exercising of any trade, profession, enterprise, activity, other commercial activity, or any other undertaking of any nature conducted for profit, whether by an individual, partnership, association, corporation or other entity, or any activity carried on or exercised for gain or profit in the municipality or school district, including the sale of merchandise or other property or the performance of services. Employment for a salary or wage is not “business,” subject to this tax.