I have a kindle, nina, and have not bought anything for it since I learnt about how Amazon is fleecing HMRC.
For anyone who has any other ereader, there is a book store called Hive, which is your local bookshop. If you order anything from Hive it can be delivered post free to your local book shop, or to your house, post free, if you do not have a book shop.
I ordered a book for my son's birthday from the Book People, then discovered I could have saved a fiver if I'd ordered it from Hive. Serves me right. Hive also keeps your local book shop going.