I have a couple of folding bookcases like that small one - pretty much exactly like it, except the metal bits are wood on mine. My dad bought them from an auction when I was five - my sisters and I had one each, but they didn't want theirs any more, so I took two, because the third one was broken. They are great to move around, because they just fold away. And the shelves are deep and fit two rows of books.

With mine, you can slot one bookcase on top of the other to make a tall one, and then it just looks like a tall bookcase. I can't see if the one you bought does that - but anyway, for you it would be cheaper to buy the big one than two small ones. I kind of like the cosiness of the shortness of them though - my other bookcases are all tall, so it's nice to have two short ones.