The 8" Slumber 1 Mattress-in-a-Box falls from $209 to $149 in the Queen size at Walmart.com. Plus, shipping is free. It also comes in a Full size for $129. This is one of the lowest prices we've ever seen on it (it's going for over $200 everywhere else) and this is one of their best-selling mattress every year with 4.5 out of 5 stars based on 6,009 reviews. Sales tax is charged in most states.