A Serta memory foam mattress makes a great gift, writes a satisfied sleeper in a recent review. While this may be true, a Serta memory foam seat or a Serta memory foam cushion make gifts just as excellent. Yes, Serta's customers are certainly enthusiastic about memory mattresses, so much so that they swear to keep them clean by using memory foam covers. Their prices are also affordable, ranging mostly from $400 to $800. However, their low price some say, is indicative of a lesser memory foam.