This Serta Amber Creek King Gel Memory Foam Mattress Set drops from $1624.99 to $649.99 to $609.99 with codes SEARS35OFF300 and SEARS5OFF50 at Sears.com. Plus, delivery is free. This is only $6 over the lowest price we've ever seen on this set, and it's usually excluded from coupons. The mattress has gel-infused memory foam that's designed to move heat away from the body. Sales tax is charged in most states.