If, like me, you do a good bit of purchasing, or at least browsing, at Amazon, you'll often find examples of pricing that make no sense. Many of these are violations of the volume-purchasing rule. For example, I've seen mp3 (downloaded) music priced this way, where buying the whole album in one go was more than buying the songs individually.
So today I'm looking at the magazines (don't ask me why, I haven't bought a magazine in years), and I see that Popular Mechanics can be purchased as a 6-month auto-renewal for $5, or for a 12-month (1 year) auto-renewal for $12. What am I missing here?