You’Re Too Greedy, Sumida-Kun! summary:

Yoshimoto Itsuki is a day trader who is always cooped up inside his house. One day he decides to take a walk and eat a snack outside and ends up bumping into a student - Sumida Gen - and making him drop his food.

Gen's tears as he looked at his precious meal on the ground ticked Itsuki's sense of responsibility and made him buy another of the same snack as an apology. Since then, Itsuki can help but buy meals to Gen all the time.