Realizing that he's spending much more money now that Hina is living with him, Nitta commits to saving money. Hina pushes back against this, as it means they won't eat fancy meals anytime soon. However, Nitta points out that Hina enjoys affordable food just as much as pricier meals.
To prove his point, they go to Utako's bar and have Hina try several dishes. After she says that she likes them, they reveal that they were all frozen dinners. When she argues that her favorite meal, salmon roe, is expensive, they prepare two bowls of it for her. After she eats them, they reveal that one bowl cost about 80 dollars and the other only four, and ask her to point out which bowl was which.
Hina is unable to do so.