The impact of everyday street floating information on children's knowledge about diverse aspects of their social world has hardly been studied in relation to their understanding about socio-economic knowledge. Though several studies have analyzed children's and adolescents' behavior related to the impact of socialization agents on their consumption habits, little is known about how and when they start analyzing several everyday communication situations concerning economic interchanges. Mexican children from different socioeconomic backgrounds were individually interviewed about diverse street information advertisings or written messages referring to economic interchanges in order to attempt understanding of an aspect of their cognitive social development. Subjects were shown a number of cards including photographs. Subjects were asked to describe the photograph and to explain its content and the type of information or communication situation that it involved. Some examples were a string with flags on the edge of a house on sale, an ATM machine, an exchange bureau, and written texts such as ‘factory prices' on the front of a department store. Results show cognitive developmental trends as well as socioeconomic influences on subjects' answers. Discussion is made taking into account theories of children and adolescents socioeconomic development as well as social and cultural aspects involved in economic literacy.