hi seb, welcome to the site.
getting a sony for your daughter is a really nice gift ! i understand your worries about cost though. but, if she likes oliver twist, perhaps she'd be interested in other classics ; there is a huge library of public domain (classic) books available for free online, including here in our ebooks section (we've got over 6000 now ! click on "e-books" and take a look around). if you could get her to read one classic per week that would be a considerable savings already. plus it's good for her culture.
also, you're right that it's still early days, so selection of more recent books is still limited, but publishers seem to be waking up now. and you're lucky : they seem to be moving a lot faster in the UK than in France... you can also help wake them up by writing a friendly letter / email to your favorite publishers, if you can't find a certain book you want in digital format, asking them when they are planning to publish ebooks of their catalogue.
let us know what you decide !