Like shipping pallets, wooden cable spools are another item that is usually found for free on Craigslist. Since cable spools are limited by their shape there are fewer repurposing options, but they make a great coffee table bookcase.
Bookshelves: Vintage Inspiration Ideas To Save Space For Tiny Room With A Traditional Bookcase And Open Shelves Interior Different Material And Sideboards And Baskets With Rug, Modern Living Room Design, Wall Decoration
I like this idea, but I think the "step" shelves need some more support. Garage shelving idea: the lower shelves actually glide out so you can step to reach top shelved items. Then they slide back to the wall.