This is thinking way to deep into it but what if she has agoraphobia and she only feels safe in her house and it's premises?
It could be that she likes the guy and wants to do a lot of things with him but can't get out of the house, so she does all of this to spend time with him
That or this is just a dumb fun manga xD
@NthML Or maybe she is earthbound spirit, who stops existing for everyone around once she leaves her house. This way she was able to stalk and learn from the best of the best.
Food costs so cheap because it does not actually exist, giving him a false feeling of being full, draining his vitality and giving him malnuitrition.
And why would she need money? She always had a dream of earning enough to support herself in the old age and her future children. But then a tragedy, a terrible accident happened! - she choked on a meat bone left inside of a meat bun and thus died in agony.
I am honestly tearing up even right now
I think I figured it out: Madoka has the power to distort reality, so she found herself a nice way of earning some money while playing around with a random salaryman and still managing to remain a hikkikomori!
I do have to appreciate that the artist actually used the masks from real Toku shows (and it kinda helps pinpoint when this was published - 2001-ish, I guess).
@agtra are there any neighbors to begin with, though? That could be an entirely abandoned section of city the guy cuts through to get to work, some abandoned factory, and Madoka-chan makes it look like the back of an apartment building....
The masks probably have nothing to do with when this was published and are just the shows the author prefered or remembers seeing/getting in an actual festival.