Walmart offers the HoMedics 12" Memory Foam Mattress in Twin for $179, Full for $199, Queen for $229, or King for $299. With free shipping, that's the lowest total price we could find by at least $110. It features a 3" firm foam balance, 3" of BreZZZ pocketed memory foam, 4.5" extra stabilizing foundation foam, and a zippered cover.