Whenever the board of supervisors of a county containing a population of 6,000,000 or more determines that any real property or interest therein belonging to the county is no longer necessary for county or other public purposes, and its estimated sales price does not exceed one hundred thousand dollars ($100,000), the county may sell, exchange, quitclaim, or convey that real property or interest therein in the manner and upon the terms and conditions approved by the board of supervisors without complying with any other sections in this article. The board of supervisors may, by ordinance, designate any county officer or officers, as are deemed appropriate, to execute sales of the real property or interest therein, provided that a notice of intention that the county officer or officers will execute the sale shall be posted in a public place for five working days prior to effecting the transfer and, at least 10 days prior to effecting the transfer, the notice shall be published pursuant to Section 6061 in one or more newspapers of general circulation within the county and shall be mailed to any person requesting special notice, to any present tenant of the property, and to all owners of land adjoining the property. These sales shall be subject to final approval by the board of supervisors.