The price savings then become obvious. Many books can be downloaded free and those that you have to pay for are much cheaper than buying the paper version. It wouldn't take long to recoup the £111 for the WIFI only version and I'm surprised that they aren't trying to push the 'green' angle a bit more.
My own book (which is a masterpiece) is available on Kindle here for just £3.44. I'd honestly recommend that you buy it even if you already have the paper version (or frankly even if you don't have a Kindle). It is selling like hot cakes (where did that phrase come from?)