After Being Rejected, I Shaved and Took in a High School Runaway (Higehiro Series)
 
Yoshida is just your average salaryman, drowning his tears in booze. On his way home one night, he finds a runaway high school girl sitting on the street. She offers to sleep with him in exchange for a place to stay – but he more honorably offers her work instead. A rom-com between the most unbalanced couple you'll ever find!