Graham Masterton's Charnel House is a buck on Amazon. I haven't read Graham Masterton yet, but I have a slew of his books I've picked up on the cheap. The movie adaptation of his book The Manitou is a hoot.
Here's a synopsis of Charnel House: A desperate and terrified old man appears at the office of John Hyatt at the San Francisco Department of Sanitation with a chilling complaint. His house, Seymour Willis insists, is breathing. Hyatt suspects a rat infestation but the truth is worse. Much worse. An ancient demon out of darkest Native American folklore lives within the walls and floorboards of Willis’s home—an all-powerful malevolent being determined to break free and wreak havoc on the City by the Bay.