King Size Memory Foam Mattresses : A memory foam mattress will help you get a good night’s sleep. **Offer valid 12/22/18-1/8/19. Receive a free Head Up 50 adjustable base (up to a $699 value) with select mattress purchases of $599 and above. Must apply promotional code ELEVATE in cart at checkout to redeem online offer. Free adjustable base offer valid on same-size mattress purchased. Split king base purchases consist of 2 bases. Amazon.com: King Size Bed Mattress. Live & Sleep Mattress Classic King Mattress – Memory Foam Mattress – 10 Inch – Cool Bed in a Box – Medium-Firm – Advanced Support – Luxury Form Pillow – CertiPUR Certified – King Size Box Spring only, Bed frame sold Zinus 10 Inch Gel-Infused Green Tea Memory Foam Mattress, King. by Zinus. $275.99 Live & Sleep King Size Mattress, Gel Memory Foam – 10 Inch Mattress – Firm Mattress – Cool Bed in a Box – Balanced Support – Luxury Form Pillow – CertiPUR Certified – Hypoallergenic – King Mattress Foundation, Platform Bed Frame, Box Spring Replacement, King 4.5 out of 5 stars 23,803 # 1 Best Seller in Beds, Frames & Bases. Invented in the 1960’s, the 76″ by 80″ king size mattress rose to popularity when most couples were used to sleeping in full beds the space equivalent of sleeping in a crib. Thirty years later, the king memory foam mattress was created. Find great deals on eBay for memory foam mattress king size. Shop with confidence. king size gel memory foam mattress king size memory foam mattress topper king size bed frame king size memory foam mattress 12 inch king size memory foam mattress 12? king 12″ inch King MEDIUM-FIRM Memory Foam Mattress King Size- Cool-Gel Infused – USA .