I don’t remember exactly how Radkolnikov’s place was described - I seem to remember dark and cold, but maybe it’s because of what his mental state is. I also seem to remember that he doesn’t own the place, but rents it.

In any case: he IS poor by the standards of his social class - which would translate to the middling sort, or maybe even gentry. He as well as his mother and sister are actually impoverished, not simply poor. I think given enough time, they’d all end up in one of the slums where the truly poor people live in the book.