PDF version is all I need. Install Xodo in my laptop. Can write notes and click the hyperlinks. My lifesaver. Without it, I'm dead.
For photocopy... I rather printout at school $0.05 each page...
For hardcopy textbook, for me either get from Carousell for free or cheapest, or mama shop at Beras Basah, level 3 is also good. There got cheap 2nd hand textbooks, including study guides... Surprisingly. Don't go to the mama shop level 2. That shop wah... Will nail you for high price even though the books are 2nd hand. Last time I went there just to check around, I overheard the uncle charged extra $10 for delivering a book to his customer's house. Wah seh. I should have helped that guy to get his books sia. But the dude made his payments already.