Purpose: While the expectancy–value theory recognizes the significance of cost as an essential component, it has garnered minimal attention in physical education. Utilizing two separate datasets, we explored the degree to which the inclusion of cost in an expectancy–value–cost model could augment its predictive capability. Method: Study 1 utilized a cross-sectional data set (N = 144) to investigate the predictive roles of expectancy belief, task value, and cost on behavioral and emotional engagement. Study 2 employed a longitudinal data set (N = 251) to assess how these variables influenced the hypothetical choice of attending physical education and cardiorespiratory fitness. Results: Cost played a significant role in explaining additional variance, surpassing what could be predicted through expectancy and value. Specifically, cost emerged as a crucial factor in predicting emotional engagement, hypothetical choice, and cardiorespiratory fitness. Conclusion: Incorporating cost as an independent construct can yield valuable supplementary insights into the determinants of students’ learning.