Oh, so that's why it's so "cheap". Well, that stinks. The Naturepedics are so expensive. And long story, but we need 2 mattresses, so those are out.
The latex mattress at sleepez.com is a normal crib size and only 200 dollars. the code CRIBS will get you free shipping as well. I just bought it and we love it. As far as I can gather, it is so cheap because they are factory direct. It is 100% natural latex though (they specify blend on other products) with organic cotton and eco wool.