Amazon with Sterling Shelf Liners has the Set-of-5 Sterling 14" x 30" Shelf Liner Mats for Wire Shelving on sale for $11 with free shipping on $35+ or with Prime. Other sizes on sale:

• Set-of-4 14" x 36" for $9.71
• Set-of-4 18" x 36" for $13
• Set-of-5 18" x 42" for $11