Students want to learn computer science due to its usefulness for future careers, however they often meet challenges in introductory courses. In the increasingly digital world, it is important to understand some important psychological consequences of such challenges: perceived costs of pursuing computer science. This study thus investigated semester-long trajectories of four cost perceptions (effort, opportunity, psychological, and emotional) and their relations to achievement, major intentions, and career intentions (N = 831). All cost beliefs showed average increases, although with nuanced differences in levels and slopes, and the four costs differentially predicted student outcomes. Interestingly, the intercept of psychological cost negatively predicted final course grades while positively predicting major and career intentions. Women reported steeper increases in cost perceptions compared to men. The findings highlight the differential functioning of cost perceptions, with implications for the importance of targeting different aspects of cost perceptions to mitigate students' barriers to success in computer science.