Let's assume a Raspberry PI costs $40 after shipping. This case costs $22 (11 GBP + 3GBP for shipping).
It's like half of a whole Raspberry Pi.
that's what I was thinking too.
Why waste money buying a case? Just make one. I made mine using the original shipping case kind of like this one http://www.instructables.com/id/Raspberry-Pi-original-shippi...
In my case I did not have a rotary tool at hand, so I just used a knife and my oven to warm it up so that the plastic can be cut easily. Just be careful not to overcut (or cut yourself).