Got some extra cash laying around? Then you might be interested in this auction of Yanks vs Sox memorabilia/crap. If it ain’t nailed down, the Yanks and Sox are selling it. And if it is nailed down, well, that’s not a problem either. Twenty-five grand is where bidding starts on the home plate used at last weekend’s opening night (all 9 Yankee footprints still on there). The rubber? $7,500. Most popular item thus far? Matsui’s clubhouse chair, with 20 bids at $1,675. Least appealing: a $500 rosin bag.