<prompt> Human: I have 135 dollars in Amazon gift cards, and it looks like the books will cost roughly 400 all together. In some cases, the books will cost less if I buy them on a site other than Amazon. Is there some kind of strategy I can use to try to ensure that I spend as little of my own money as possible? The answer is probably common sense, but Im extremely bad at strategical thinking, as well as anything involving numbers.Please let me know if this doesnt make sense or if I havent given enough information. Edit: I was looking for ideas specific to the scenario I described, but thanks to everyone anyway for the general advice.  <response>: I never bought textbooks until I was 100 positive I would need them.Check with your professor to see if the library will have copies you can reserve for a few hours. This may require you to go to the library at odd hours as other people in your class will likely do this is as well. Do you know anyone who may have just finished the class and still has the textbook?What will you need the textbook for? Homework problems? Just reviewing material? Is the material covered on the slides enough? In class readings?Can you split a textbook with somebody?Many times Id go entire quarters without buying more than one text book besides despite taking 4-5 classes. 