Otonarisan to Hajimeru Setsuyaku Seikatsu.: Denkidai no Tame ni Issho no Heya de Sugoshimasenka?

A highschooler who's living by himself - Mamiya Tetsuo is trying to save money, just like the girl next door, Yamano-san. They tried things like making their own lunch bentos and sharing a big loaf bread.... But it wasn't enough... And summer is coming, the expenses will be going up even more due to