What does it mean to have a monopoly on a product that costs nothing? Saying google has a monopoly on search is akin to saying that Tolkien has a monopoly on hi

What does it mean to have a monopoly on a product that costs nothing? Saying google has a monopoly on search is akin to saying that Tolkien has a monopoly on high fantasy novels; just because it's the most popular on the market doesn't mean its your only option, and the same is true of search engines.