Walmart offers Hyper Tough 15-3/4" x 6" Shelf Kit 3-Pack for $13 (reg $16). Free shipping on orders over $35. 

Product Description:
Hyper Tough 6 in. x 15 3/4 in. Rustic Gray Laminated Wood Shelf with Black Metal Brackets and Screws, Multi-purpose wall shelf that installs easily in the laundry room, garage, crafting room or other common areaTextured, rustic gray finish shelf board

• Provides extra storage in any living space
• Multi-purpose wall shelf that installs easily in the laundry room, garage, crafting room or other common area Textured, rustic gray finish shelf board
• Shelf brackets and mounting hardware sold separately Shelf dimensions: 6 in. x 16 3/4 in. x 5/8 in.