The last three semesters I have purchased most of my books through e-bay, amazon, and one private. Three of teh books we never used. I checked with the school listing, waited for the syllabus, and talked to the teacher if possible before classes started.
You must be sure which edition the teacher wants, check carefully when ordering online which edition and if there is a study guide/CD/workbook that is included. You can find this info on your school site.
I saved over $600 this last year on books buying online.
Get your notebooks, pens, pencils, etc, from the cheapest places you can. Keep the receipts for tax purposes. Know which pen, pencils, etc. you like and will use. Don't get funny or fancy. Use what you know. I bought a wheeled backpack last fall and plumb wore it out so need a new one this next semester. It saved my arms, hands, and back. Reserve your energy for studying. Good luck.
PS- thanks for the tips on the laptop. I will check it out as I am tired of 3 people needing the two computers we have. Doesn't work. DD needs it for work and DH and I for school.