Free live free.

A group of four down-on-their-luck strangers respond to a classified ad offering a strange bargain: live free of charge in an old man's house, and help him to prevent the city from having the building demolished.

This is a strange, often comic, sometimes frightening novel that sticks so closely to depicting only what the characters themselves notice that, if you're not paying close attention, it's possible to miss that you're reading a science fiction story until the very last chapter.