This two-inch Comfort Rx Orthopedic Gel Foam Mattress Topper sells for $15 in Twin and drops from $20.88 to $16.31 in Twin XL, $22.88 to $18.32 in Full, $27.88 to $23.08 in Queen, and $34.88 to $28.63 in King at Walmart.com. This is the best deal we can find for this topper. Elect free store pickup if available in your area. Otherwise, value shipping is $4.97 or free with $50. This gel-infused foam topper provides firmer comfort than memory foam. It sports five contoured zones for added support. Sales tax is charged in most states.