Consumer behavior is a scientific branch that refers to the behavior of the end consumer in the buying process. The decision to make the final purchase is the result of many factors, specific to each individual, and these are primarily economic, psychological, social, personal and cultural factors. By identifying and understanding the factors that affect their customers, brands have the opportunity to develop a strategy, marketing message and advertising campaigns that are in line with the needs and ways of thinking of their target consumers. This paper deals with psychological models of consumer behavior. The main goal of this paper is to obtain an understanding of the importance of the scientific branch of consumer behavior, basic models of consumer behavior and to get acquainted with the main psychological factors that influence the customer's decision to buy a particular product. The paper will use a quantitative research method (survey) to determine the habits and main factors influencing the decision to purchase certain products in online stores.