This article presents the assessment of two educational secondhand clothing markets developed at two high schools in Albacete. One of them involved money and the other was based on barter, and both included an awareness-raising phase to promote responsible consumption. Although all students were involved, only those who organized the experience were surveyed (N = 40, 21 females). Data were gathered after the experience, in student´s regular classrooms. A qualitative methodology was used, combining focus groups and an open-ended questionnaire. Findings were similar in both groups: the experience was positively perceived, although there was an initial stigmatized preconception surrounding secondhand clothing; it also helped students learn and become aware of the environmental impact of clothing, making them reflect on their consumption habits and change them. Students also perceived some barriers to reducing their consumption. Thus, secondhand markets can be powerful educational tools to raise awareness and change behaviors toward more pro-sustainable choices.