Walmart offers the Sealy Posturepedic Optimum Latex Dreams 10" Cushion Firm King Mattress for $490 with free shipping. That's $680 off list and tied with last month's mention as the lowest price we could find. It features a 2" layer of OptiCool gel latex foam, 1" layer of OptiSense premium latex, and 7" layer of OptiCore support.

It's also available in Twin XL for $290 with free shipping. That's $410 off list, tied with last month's mention, and another price low.

Note: The frame and foundation are sold separately.