i went to the Nuts for Mutts fair last year and they had those (ellie actually stood on one in front of the camera...but they never aired it
)
Anyway....that thing is basically disgusting because there's a tray underneath it...that you have to empty.
when we got gruffi, he was 5 weeks old and i took him to my condo in san diego...and i had a balcony off of my room....so all i did was put a really really large sheet of plastic, and i put sod on top of it. it would last for a couple of weeks. and sod is around $1.50 for a piece that was 4x2 inches.
and after they pee, just add a little bit of water on top. it will last longer.