This two-inch Comfort Rx Orthopedic Gel-Infused Foam Mattress Topper sells for $15.52 in Twin, $14.99 in Twin XL, $19.85 in Full, $23.08 in Queen, and $28.63 in King and California King at Walmart.com. This is the best deal we can find for this topper. Plus, through tonight, shipping is free. 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.