Get up to 60% off mattresses during the Memorial Day Sale at Walmart.com. Shipping is free for most items, and many items also qualify for a pickup discount. The pictured Slumber 1 8" Mattress in a Box goes for $159 in the Queen size, the lowest price we could find by $37, and this Modern Sleep Advantage 8" Plush Innerspring Mattress goes from $469 to $170.98. Also check out this Lucid 10" Dual-Layered Gel Memory Foam Mattress, which goes from $259 to $192 in the Queen size. All of these mattresses have an average rating of 4.5/5 stars. Sales tax is charged in most states.