I have a good feeling this is going to be one of those trainwreck mangas that you can't pull yourself out of because you're already 100 chapters deep. Fuck me.
Yup. That mean the payment is the potential interest from that 3 million yen. I don't read Rent a Girlfriend, but would anyone bother comparing the price (assuming its's 5-10%/year)?
If she was that much money in debt, for sure she was doing some sort of prostitution to help pay it off. She jumped straight into sex mode too since she thought that was what he wanted out of this. Not that its her fault, just sucks..