The paper examines the effect of different payment modes on hedonic post-purchase product evaluations over time. Two theoretical frameworks—mental accounting and cognitive dissonance—suggest such an effect, but are contradictory regarding its direction. Additionally, the paper examines whether prospective consumers are able to correctly predict post-purchase evaluations and the effect of payment mode over time. In an online survey, hedonic evaluations of 346 car owners in three ownership phases (one, two, and three years after purchase) were measured and compared to predictions of 75 prospective car owners. Two different payment modes (down payment vs. installments) were distinguished. Results showed an interaction between payment mode and the hedonic evaluation of the car over time. In the first and third year, the evaluations by both groups were similar; in the second year, the installments group rated their cars more favorably than the down payment group. Neither of the two theoretical frameworks—mental accounting or cognitive dissonance—is sufficient to explain the observed relationship between payment mode and evaluation over time. The results suggest that mental accounting theory should be expanded with elements of cognitive dissonance. Regarding predictions, prospective car owners did not foresee the effect of payment mode on evaluations over time. Mispredictions are of practical relevance because they can influence consumer decisions. © 2011 Wiley Periodicals, Inc.