"There's an explanation somewhere on teh Amazon site, that explains what happens, but basically, the book was at $0.00 when the RSS entry was written. Depending on how long it takes you (or any other tool, such as Zero Dollar Books) to read that particular RSS entry, the discount period may have ended. A typical example is where I catch up on my feeds on a Monday -- I tend to miss the Satruday and Sunday freebies, because the price has gone back up by the time I see the feed." - martin english