The increasing prevalence of free-to-play games with in-game purchase options has prompted research on player behavior, particularly concerning with pay-to-win (P2W) mechanics. However, existing research focuses on the financial aspects driving P2W behaviors, leaving the psychological factors underlying players’ behavior changes largely unexplored. Specifically, limited attention has been given to understanding the transition of players from free-to-play to P2W models. This study addresses this gap by examining the psychological underpinnings of players’ behavior changes associated with P2W. By integrating multiple theoretical frameworks, including self-determination theory, social comparison theory, and cognitive dissonance theory, we propose a comprehensive research framework to explain the motivations and mechanisms behind players’ shift from free-to-play to P2W participation. The study also offers insights into the research and practical implications of understanding this behavioral transition, providing a foundation for future studies and informing game design strategies.