In recent years, as the economy in Taiwan grown strongly, the lifestyles changed into a modern pattern, which had placed the traditional society. In the new, fashion, and modern lifestyles, here comes a new type of consumption. In order to adapt the new environment, marketers have developed many kinds of marketing skills to promote the services or products they provide. Therefore, sales promotions have been significantly over the years. Sales promotions are short-term incentives to encourage customers to make a purchase. As consumers are exposed to the sales promotions, their perceptions of the sales promotions play an important role in leading consumers to make purchase decisions. In sum, the purpose of this research is to discuss the relation between sales promotions and the purchase likelihood; we also try to explain how the cognition from consumers impacts their purchase likelihood. Thus, the following are our purpose: 1. To evaluate whether the sales promotions from Watsons can affect the quality perception of consumers. 2. To understand the relation between the internal reference price and perceived transaction value. 3. To analyze the relation between perceived acquisition value and purchase likelihood 4. To explore how the purchase likelihood change when the anticipation of sales promotions fail. 5. Discuss the differences of cognition toward sales promotions in Watson within genders. In this research, I administered a questionnaire to explore the data from 223 participants. The findings are as followed: 1. The sales promotions from Watsons have significant impacts on quality perception of consumers. 2. Consumers¡¦ internal reference price has significant impacts on perceived transaction value. 3. Perceived acquisition value have significant impacts on purchase likelihood 4. The failure of anticipation toward the sales promotion will decrease consumers¡¦ purchase likelihood. 5. There¡¦s no difference of cognition toward sales promotions within genders.