Over the last few weeks, Kindle book prices have been a bit odd - as independent authors discovered that they would get a lower price and the same earnings for a $1.00 book versus one at 99 cents (and could earn more by setting the price at $1.24, which was discounted to $.99), a large number of them started changing prices. Some authors were doing so several times a week (or even a day, as they didn't realize it could take a few hours for the pricing genie to set the discounts). Just over a week ago, it seemed that the automatic discounting was stuck and some found their prices frozen - they set their list price to $1.00 or $1.24, but the sale price stayed at the previous level - I saw these at anywhere from $3.19 to $9.99, which it turned out was the magic discount for any indie title that had a digital list price of $24.99 or less and where the 20% discount was over $9.99 (and some authors intentionally set their prices a few pennies higher, as they didn't want their books discounted to the 9.99 level).
Since the first of July, a number of these authors have found that their books increased in price in the Kindle store - the automatic 20% discount that they had before was removed (one poor author had his set to $200.00 (The Grove), rather than his list price of $1.24 -- although I feel more sympathy for the 23 people who one-clicked his book from the end of the sample and were charged $200.00; hopefully they noticed and get their refunds). No one knows if the discounts will return and a few authors still have discounts set (these appear to be the better selling titles amongst the indie authors).