FutureBook has an article about this given the opening of the Amazon Germany ebookstore. Here’s an excerpt:
… The top selling Kindle Edition is British writer Simon Beckett’s Verwesung, and the selling price is €19.99. What’s that you say, €19.99? By contrast, the bestselling Kindle Edition on the UK chart is Michel Faber’s The Crimson Petal and the White priced at £1.47,
…. there are only 18 titles in Amazon’s top 100 UK Kindle bestsellers that are priced above £3. By contrast, there is only one title in the German list priced below €3, and that is a self-published English-language romance book. Most are priced at €8.99 and above.