The paper presents the concept of Solidarity Economy proposed by the Austrian-Brazilian economist and professor Paul Singer who passed away in 2018 at age 86 years in his home in São Paulo. Singer arrived at the concept of Solidarity Economy by mixing utopian socialist thought originated in Europe during the Industrial Revolution with the wisdom of Latin American working people to find alternative paths to the capitalist economic system. Following the teachings of Paul Singer, we, as practitioners and academics, report the first stage of the formation of a popular cooperative in the sector of recycling that occurred between 2019 and 2021 in the Town of Goiás, Goiás, Brazil. Our analysis of this collective endeavour leads to two main lessons: first, Solidarity Economy is an even broader proposal of an alternative to the capitalist economy than Paul Singer imagined, because its roots are not restricted to the European cooperativism of the nineteenth century, and second, economics must be taught in more popular way because the most urgent economic problems affect primarily the working people.