Waterstone's is not the only place where you can buy ebooks. Take a look at
fictionwise or
Books On Board. They all stock new stuff, and you can even get rid of the DRM if you download in LIT format. You can also download all sorts of free books from places like
this forum,
feedbooks,
manybooks,
munseys and there's more free books on
gutenberg than you could read in several lifetimes.
There's more than one way to skin a cat.