As geneven mentioned there are a lot of free books as well as ones that you need to pay for. I'm not sure about on other Amazon sites, but on the UK site you can see a list of the top 100 most popular free books (along with the top 100 paid books) here: http://www.amazon.co.uk/Bestsellers-...QR09FT1NW68QF3 You can also click on the different categories on the left to see the top 100 in each genre too.