This 8" Spa Sensations Memory Foam Mattress in all sizes is on sale with prices ranging from $129 to $199 at Walmart.com. Plus, shipping is free. This is one of the best-selling mattresses at Walmart, and over 3,000 reviewers have given it a 4.4 out of 5 star rating. Twin size drops to $129, Full to $149, Queen to $169 (it's going for $291 at Amazon) and King and Cal King drop to $199. These are all time price lows on every size but twin! Sales tax is charged in most states.