Some text publishers offer textbooks online.  I don't have much information as to how the online system will work and I was not given specific pricing or discount information, but if you are interested, here's a link

 www.ichapters.com  

 One publisher (Thomson Southwestern)  told me that a discounted option usually applys to online text purchase, but did not make any promises about pricing options that apply to specific textbooks.  Please note that these prices are "up to" a particular discount, so I am not certain what/if any discounts specifically apply to a specific text.

"New texts up to 25% off, shipped free.

• eTexts up to 50% off.
• eChapters (individual electronic chapters) as low as $1.99."

Please be sure to check the syllabus carefully so you order the correct textbook.   Many authors write several texts on the same subject -- check the order of the authors' listed names (names should be in the exact order as shown on the syllabus) and check to be certain that the title of the text is correct.