Cat Shelves - About a $50 project including the bed at the top. 4 - $6 Ikea Lack shelves, 1 - $5 shelf at the top from Ikea I don't remember the name, 3 - $.50 shelf supports for top shelf, $20 dog bed from Petco, $2 industrial Velcro from craft store.
Set of Four: Three Floating Cat Cube Shelves and One Floating Cat Bed | Floating Cat Shelves | Cat Perch | Reclaimed Wood Shelves
"Put kitty on a shelf: In the words of Jackson Galaxy ”Cats need vertical space; it enables them to survey their world from a safe perspective.” If you don’t have room for cat towers, or just don’t like their aesthetic, cat shelves are a great alternative. The cat shelves in my apartment double as modern art!" http://www.urbanpethaus.com/content/wave_perch.htm