And again, she SHOULDN'T know almost anything about his actual financial circumstances. She heard him say he's poor to the truck driver. Yeah, she basically already knew that. No surprise there. She has no reason to know he puts toys in capsules for hours for money (see my comments on chapter 13).
Honestly, this is making me both pity and dislike Souta. I pity him because I can somewhat understand why he's doing these things, literally using money to buy affection from Haru. I dislike him because what I don't understand is why Haru. Because of her..."kind smile"? That's what he said last chapter. If it were for something like Haru seems more genuine and upfront than his classmate, that would make sense. Something like at least I know that she's doing this for money whereas I'm suspicious about Takasaki's motivations. He thinks none of that. And yeah, I get that he's confused about what he's feeling. But he's going into a situation that literally looks more toxic than almost any of his alternatives.