that seems a bit harsh.
But honestly, if you can't build one out of cardboard, you aren't creative enough to be bothering with the RPi. Go get yourself a Facebook account instead.
He does have a point, though. A case in particular is pretty easy to improvise. As a somewhat unrelated example, I used to keep my model paints in an empty box that used to hold teabags. Something like that would be about the right size for an RPi (maybe a little too large, but it can be cut down, of course). When I ran out of space in that, I could have gotten a dedicated carousel for them, but I didn't want to spend the money, and so now both my modelling supplies live in the bottom part of the (somewhat larger) box in which a model I already built came. My first thought for the RPi was Lego, though.
Things like these are why I have a giant pile of cardboard (and various other materials) in my closet. One can find a use for all sorts of things with some imagination.