Have you heard of Booklr? This is a market research firm that is focused entirely on books. Sign up with their service and you can get pricing data on virtually any title published in the US.
Earlier this week they posted an infographic which compared the Top 100 titles in the Nook and Kindle stores. Amazon bet B&n in several ways, including lower average price ($6.48 vs $8.94), s well as having far more titles under $2 (35 vs zero). It's fascinating comparison.
The infographic is after the break.