The purpose of this study is to determine whether planned or unplanned purchases impact a consumer's willingness to pay for a subsequent purchase. We investigated the moderating roles of the justification heuristic and two different payment methods (individual payment vs. bundle payment). Three hypotheses were tested using a two-way ANOVA and an independent sample t-test. Our findings led us to the conclusion that, due to a conversion of mindset, a consumer's willingness to pay for a subsequent purchase will be higher in an unplanned precedent purchase situation than in a planned precedent purchase situation. For the planned purchase situation, a consumer's willingness to pay for the subsequent purchase did not turn out to be significant despite the use of the justification heuristic. For the unplanned precedent purchase situation, however, a consumer's willingness to pay for the subsequent purchase was found to be lower in the situation with the justification heuristic than in the situation without. This study also shows that a consumer's willingness to pay for a subsequent purchase will be higher in a bundle payment situation than in an individual payment situation.