For students there are scholarships that can support the costs arising from the life of the university, which you can find here: https://www.polimi.it/studenti-iscritti/tasse-borse-e-agevolazioni-economiche/altre-borse-di-studio-e-premi/. In addition, the Politecnico di Milano announces bags with economic requirements and merit, which include, in addition to a fixed amount even of places in residences or a contribution to the rent, and a good daily. All the information, and the mode of participation can be found here: https://www.polimi.it/studenti-iscritti/tasse-borse-e-agevolazioni-economiche/il-diritto-allo-studio-universitario-dsu/.