Purpose: The study aims to investigate customers' emotional and behavioral responses to price promotion in omnichannel retailing through the integration of the expectancy-disconfirmation theory, feelings-as-information-theory and regret regulation theory. Design/methodology/approach: An online survey was designed in Qualtrics and distributed by an online survey to collect data from 786 (main study) and 150 (a follow-up study) customers from the USA. The participants were randomly assigned to different scenarios related to the need to purchase a toothbrush, laptop or health supplement. After the first purchase, the participants received a discount on the same product that has just been purchased. The discount can be used at an online store or a physical store. The three levels of price promotion after the purchase were 10% (low), 25% (moderate) and 50% (high). Findings: The study found that consumers are likely to feel more surprised and less discontented when being offered a higher discount. The emotions further significantly impact their anticipated regret. Further, different discount levels influence patronage intention and omnichannel usage via emotional responses and anticipated regret. These relationships are moderated by product involvement. Originality/value: The study extends knowledge of price promotion and provides insights that can assist retailers in increasing the effectiveness of their sales promotion strategy. Addressing the lacuna in the current literature, which predominantly focuses on the cost and benefits analysis of sales promotion, the study revealed that cross-channel price promotion results in consumers' sophisticated emotional responses.