Walmart offers the Comfort Classics 3M Scotchgard Harmony Waterproof Mattress Pad in several sizes from $14.27 $18.29, as listed below. Choose in-store pickup to avoid the $5.99 shipping fee. For comparison, some retailers charge about double these prices. It fits mattresses up to 18" deep. The deals: Note: Queen size is also available for $20.35 (low by $14)