You've got to admire a person who can create a business out of nothing. Barton Steiner saw a potential in selling stuff that the Yankees had used to fans who want them. According to this article, he has talked the Yankees, and a lot of other sports teams, to sell him their used products, from bases to rakes to dirt, so that he can sell them to fans who are willing to pay well for this memorabilia.
So now Yankees groundskeepers change the bases several times a game so Barton can sell them to fans for hundreds of dollars. Very clever!