The legislative body may purchase, lease, exchange, or receive such personal property and real estate situated inside or outside the city limits as is necessary or proper for municipal purposes. It may control, dispose of, and convey such property for the benefit of the city. The legislative body shall not sell or convey any portion of a water front, except to the State for use as a public beach or park, unless by a four-fifths vote of its members the legislative body finds and determines that the water front to be sold or conveyed is not suitable for use as a public beach or park.