I have made many of these fun little shelves from scraps of wood.
They go together quickly, using the nail gun for most of it. I do screw the supports and the shelves in from behind to secure them, but the rest is all with the nail gun. Just cut your scraps the same size, lay them out and determine your width, then cut 2 shelf supports and two larger boards for shelves and 2 random spindles.
Nail it all together, a couple screws into the supports and the shelves and that is all it takes!