Students' perceptions of cost are important predictors of academic and motivational outcomes. Though cost has been described as the anticipated effort one must put forth on an activity and what an individual sacrifices to complete a task, no known work has examined the extent to which anticipated cost beliefs predict experienced cost or whether anticipated and experienced costs are differentially predictive of academic and motivational outcomes. We used dynamic structural equation modeling to explore four dimensions of cost (task effort, outside effort, loss of valued alternatives, emotional cost) as anticipated and experienced beliefs, to examine the extent to which each predicts mathematics achievement and STEM career intentions in introductory college calculus courses. Data were collected using a combination of traditional surveys, diary surveys, and institutional records. Overall, students who anticipated high cost at the beginning of the semester tended to experience high cost during the course and had more variability in their experiences of cost. Cost beliefs appear to be differently associated with grades, however, with anticipated cost associated with higher course grades and experienced cost associated with lower course grades. Results suggested that anticipated and experienced costs are, to a certain extent distinct phenomena with unique effects on student outcomes, and that examining them as such may have important implications for theory and practice.