For the past few years an economic sociology has sought to explain the role of the various devices and operations comprising the market relationship. In this paper the author considers the specific case of consumers' actions in the purchasing situation. Using an original method for analysing the shopping process, she collected a corpus of situations involving choice. She represents the heterogeneity of these types of choice in the form of three ideal-types: routine, selection, and deliberation. These operations underscore the highly cognitive dimension of consumers' involvement in market relationships but also show consumers' ability to come to terms with moral dimensions.