You'll find tons of classics and other favorites, like: For Amazon Prime members the Lending Library is a super cool perk in which you can lend out your ebooks and "borrow" a book for free each month. It's definitely much easier to pack all my books with me in electronic format than it is in real life...
It's not quite like your local library's lending power, but it is pretty awesome if you'd like to try out a book but are not so sure about paying for it yet. just ask the strong guys who helped carry all my heavy boxes of books when we moved into our new home! No matter your listening preferences, Amazon's got a gazillion songs and albums to choose from.
One thing not to miss are children's books that have been created as apps (thus they are in the App section).
These interactive books, which usually have the option to automatically be read by the app itself, are usually quite adorable and very appealing. During the summer before my fifth grade year our TV broke and I started biking to our local library to browse through the book shelves. I enjoy physically holding a book, but now I also love having ebooks on my Kindle Fire.
Just like the print copies, it's cheaper in the long run to pay for a subscription vs paying for each individual issue.