a ten inch fire HD tablet on black friday will probably go for £99. i paid about that on BF last year, and that will sync your reading position as others have said. it will also run calibre companion and epub reader apps, giving you even more choice.
battery life for reading should be ~12 hours, maybe more
And it will stream prime video in HD when you want a break from all that reading
220+ ppi with the full HD screen so plenty crisp enough for reading, & it can do the
less blue light at night trick
no one does a 10 inch e-ink at anything close to that price
actually, any 10 inch android tablet with the Kindle app will do the job, but a proper android full HD tablet will cost more