Amazon.com has consumer psychology pinned down just right and I fell right into their game. But that's fine with me, because I got a good deal.

I was looking for an extra iPod firewire cable so I don't have to unravel existing cables every time I want to sync. This is a purchase purely of convenience and laziness, but it will improve my music experience overall.

The cable was $19 and change, but free shipping doesn't kick in until you reach $25. So I looked around for some music I want and found the latest Gwen Stefani album and (finally) that Lostprophets album, Start Something, with "Last Train Home."

I also love the way Amazon shows you your order total. If you get free shipping, they add on the amount and then subtract it. They could have simply line-itemed the shipping cost at zero, but by showing you the process of adding and subtracting $7.50, they further convince you that you got a good deal. Well done.