Walmart continues to offer the Beautyrest 3" Reversible Memory Foam Mattress Topper for $30. Choose in-store pickup to dodge the $5.99 shipping fee. That's tied with our mention from last week and the lowest price we could find by at least $30. It comes in twin, full, or queen, and features 1.5" of sculpted memory foam over 1.5" of supportive foam.