We are ready for the third R-Lab, the monthly appointment where we co-work together on a real data science problem using R. This time the R-Lab is promoted by nothing but the Assessorato alla Partecipazione, Cittadinanza Attiva e Open Data of the Comune di Milano! We will access their municipality budget data, and use one day of joint work for designing and realizing an R Shiny app that allows citizens to visualize and explore the city revenues and spending info.