Is anyone familiar with this sandbox?

I posted this in the baby board as well, but was hoping that maybe someone with an older child would be familiar with this type of sandbox--I know that Home Depot sells a similar style online...:

I am really looking to get a sandbox for my kids this year--I know I want something large and somewhat deep, so it'll hopefully be used for a few years. I'd like to stay away from chemically treated lumber, if possible. I was looking at this box:

http://littlepeoplescove.com/images/...ex_mainimg.jpg
from http://littlepeoplescove.com/sandboxes/sandboxes.htm

Is anyone familiar with this type of box? Or does anyone have any other suggestions for a large box? We would be willing to build one, but am wondering if the cost of good, weather-resitant wood would be about as expensive as this 'pre-made' box. Would love your opinions! Thanks :).