Floating shelves are great to add a modern aesthetic to your space, ... the shelf has a spacious, 10-inch-deep surface to hold several books, ... 12 or 18 inches wide.

Bayka Floating Shelves, From $18 (was $37) at Amazon. Get it. For $18, you'll get three shelves. There are three different size options: 15.7 inches, 22.5 inches, and 36 inches, ...

Once the shelf is in place, the cleat is hidden from view and the shelf appears to be floating unsupported. The hollow shelf measures about 3 inches thick x 6 inches deep x 22 to 24 inches long.

Get it. For $18, you'll get three shelves. There are three different size options: 15.7 inches, 22.5 inches, and 36 inches, although only the smallest option is available for under $20.