Just for fun, I clicked on the link and looked for SICP. Amazon gave me a price of $115.44. If you look at the bottom, you'll see a link for the same book, only Amazon is selling it for $69.34!

What is the difference between the two? The links are:

$115.44 : http://www.amazon.com/Structure-Interpretation-Computer-Prog...

$69.34 : http://www.amazon.com/Structure-Interpretation-Computer-Prog...

Aside from price, the only difference that I can make out is that the cover for the more expensive version is a lighter shade of blue. What it looks like is that Amazon is charging a lot more if you buy SICP as a textbook rather than as a regular book.