Help me choose an e-reader for 9 yr old

[scrappydappydoo]

I'd love to get DD an e-reader for Christmas but I'm unsure which one is best:
She devours books and so I want a good selection of children's books that are cheap or can loan from library.
She has a tablet but I would like to get her a separate e-reader that is not back-lit as I think it would be easier on her eyes.
Needs to be under ??100

I have a kindle which would be good for linking up but not so good for cheap books/library loans.
Any advice?

I have a nook which is handy for library books.

But I'll be honest, it's nowhere near as user friendly as a kindle. But in terms of being easy to read, not sore on your eyes etc, it's fine. Not terribly dear either.

Otoh the nook is not great if you want to buy books - Barnes and Noble don't have a great selection and what they do have is very expensive.

Ah yes you see this is my dilemma - I love my kindle but it frustrates me no end that I can't get library books and I can just see it becoming more expensive..