Freemium strategies (offering both a free and paid version) are a commonly used approach to sell digital goods. Academic research into freemium strategies is distributed across disciplines, and each study typically focuses on a single type of freemium strategy within a specific context. This chapter provides a review of the literature on freemium strategies, highlighting the central insights across these studies. The goal of this review is to provide a resource that researchers can use to gain an overview of research into this topic. We then discuss areas where there are opportunities for further exploration, and where the anecdotes that are often used to discuss freemium strategies and the reality of the academic literature do not align. We conclude by highlighting areas for future research into this domain.