The feature of group buying is that the price will go down as the accumulated orders are increasing. However, consumers will not know the final price until the end. As a result, consumers can only make decision based on the final price forecast of group buying. The final price forecast might be different depending on different pricing strategies of group-buying models and if there are competitions from posted-price stores. The purpose of this research is to understand how consumers¡¦ internal reference price and final price prediction of group buying would be influenced when facing different price curves in different market competition environment. The difference between the internal reference price and final price prediction of group-buying indicates the consumers¡¦ transaction utility. In addition, if consumers¡¦ perceived transaction utilities affect their intentions and behavior of joining group buying is another research purpose. In this research, there are three different pricing strategies, decreasing, neutral, and increasing based on the initial price, discount size and final price. For the market competition environment, it manipulated by if there are other posted-price stores to be chosen or not. The research result indicates that increasing price curve, which has higher final price, make consumers¡¦ final price prediction of group buying higher than the others under the best condition. On the other hand, it indicates that decreasing price curve, which has higher initial price, make consumers¡¦ final price prediction of group buying higher than the others under the worst condition. Consumers¡¦ internal reference prices are mainly influenced by market price information. When there are other posted-price stores to be chosen, consumers¡¦ internal reference price are higher averagely. In addition, the higher consumers¡¦ perceived transaction utilities are, the higher consumers¡¦ intentions to join group buying are. Finally, it shows consumers¡¦ intentions to join group buying have significant effect on their actual behavior.

Recently, online group-buying has been a popular business model. It was observed that many characteristics of online group-buying are potential stimuli of impulse buying. Therefore, we target traditional online group-buying and e-coupon group-buying and try to explore the characteristics of online group-buying stimulating impulse buying. Based on the literature review and empirical data collection, we identified five characteristics of online group-buying which may stimulate impulse buying. They are group-buying discount, time pressure, social interaction, perceived shopping convenience and consumption deadline. The data were collected through online questionnaire. The analysis result shows that the five characteristics of online group-buying indeed cause impulse buying. Further, we also explored whether the impulse buying behavior will be moderated in different situations. These moderators include group-buying model (traditional online group-buying vs. e-coupon group-buying), transaction price level, relationship with the group-buying initiator, product type and group-buying experience. The result indicates that the impulse buying behaviors are easier to be stimulated in the following situations: traditional online group-buying, lower transaction price, familiar with the traditional online group-buying initiator, non-food product and more experienced consumers of online group-buying.