Groupon offers the AC Pacific 6" Aloe Vera Queen Memory Foam Mattress for $189.99 with free shipping. That's the lowest price we could find by $106. It's made with 1" of 3-lb. memory foam and 5" of foam support, and it measures 80" x 60" x 6".

It's also available in full size for $189.99 and twin size for $124.99, both with free shipping. They are price lows of $73 and $74 respectively.