Brock Purdy, quarterback and MVP favorite for the San Francisco 49ers, is making a paltry $870,000 in base salary this season. He is part of his four-year, $3.7 million contract that he signed as the last pick in the 2022 NFL Draft. He remembers, he lives in California and you might as well cut your salary in half to account for taxes. As of October, Purdy stayed with an offensive lineman to save on rent.And even if the 49ers wanted to give Purdy a raise this season, they won’t be able to. He could become the first 49es player to…