There are wide range of meetings ranging from Parent teacher meetings in schools to annual general meetings of shareholders of listed companies to the more mundane internal meetings in most businesses with more than 3 employees.
The cost and effort of organizing a meeting varies to a very great extent depending on the number of people who are attending the meeting, purpose of the meeting and where it is being organized.
Office meetings are usually the easiest to organize , as everyone is getting paid a salary and is present in the office, so they will attend the meeting if they are told to do so and do not have any urgent work to be done.
Even then, some additional effort is required by the meeting organizer to inform people about the meeting, organize the agenda, and to arrange for a meeting room where matters can be discussed.