More textbook prices

I pulled up one of my advisee's course listing for this semester and looked up the cost of textbooks. It turns out that the bookstore has an online site, of course. The only question I have is why does anyone buy any books from the bookstore???

Biology 113
Biological Science by Freeman - package
Bookstore New $76 Amazon New $70
Bookstore Used $57 Amazon Used $20

Chemistry 132
Chemical Principles - package (used for fall and spring)
Bookstore New $335 Amazon New $237
Bookstore Used $ 251 Amazon Used $119

German 102
English Grammar for Students of German
Bookstore New $19 Amazon New $17
Bookstore Used $14 AmazonUsed $13

Na Klar
Bookstore New $222 Amazon New $109
Bookstore Used $167 Amazon Used $30

Math 165
Linear Algebra
Bookstore New $148 Amazon New $99
Bookstore Used $111 Amazon Used $15

TOTALS
Bookstore New $800 Amazon New $532
Bookstore Used $600 Amazon Used $197