On Saturday night, just one day after Milwaukee Bucks big man Giannis Antetokounmpo delivered another stat-sheet-filling performance against the New York Knicks (25 points, six rebounds, two assists, two steals), one of his 2013-14 Prizm Basketball Autographs was putting up some impressive numbers of its own, changing hands for a whopping $180. That final price may not seem staggering by…