The Common Core State Standards (CCSS) for English language arts and mathematics represent a sea change in standards-based reform and their implementation is the movement's next -- and greatest -- challenge. Yet, while most states have now set forth implementation plans, these tomes seldom address the crucial matter of cost. Putting a Price Tag on the Common Core: How Much Will Smart Implementation Cost? estimates the implementation cost for each of the forty-five states (and the District of Columbia) that have adopted the Common Core State Standards and shows that costs naturally depend on how states approach implementation. Authors Patrick J. Murphy of the University of San Francisco and Elliot Regenstein of EducationCounsel LLC illustrate this with three models: