Help me find a yaoi manga please!

I remember it was a yaoi manga about a college guy studying economics, and one day when he leaves his house, he sees the man who has been having sex with his neighbor outside smoking, and then he asks the boy to borrow some money. When he returns, the boy sees the other man waiting for him to pay him back, saying that he doesn't like owing anyone money. They then start having sex in exchange for the student mantaining him, but in the end it turns out that the man is a super wealthy economist and they live happily ever after.

I read it years ago, so I don't remember the details very well, but if anyone can help me find it, I would really appreciate it!