Max Weber was born 150 years ago on April 21. I saw no note of it on any of the blogs I follow written by economists of the Austrian School. Besides being the author of the most important book in sociology of the 20th century, Weber has some indirect relevance to free banking because he recognized that the key question for the practicability of a socialist economy is whether it can calculate efficiently (Economy and Society, part I, chapter 2, section 12, "Calculations in Kind"). The key theoretical addition to arguments for free banking over the last generation is a form of Ludwig von Mises's socialist calculation argument, which Weber slightly preceded and which he acknowledged in a note added while "Calculations in Kind" was in press.
In the same book and chapter, section 6, "Media of Exchange, Means of Payment, Money," Weber remarks, "The formulation of monetary theory, which has been most acceptable to the author, is that of von Mises." Finally, he observes in passing near the start of section 32, "The Monetary System of the Modern State and the Different Kinds of Money: Currency Money," and near the start of section 34, "Note Money," that issuing coins or notes need not be a monopoly.