<p>In what cases are these alright to get? One of my textbooks costs $80 for the current edition, and $10 for the 2001 edition.</p>
<p>The problems get switched around; ask your professor if you can use the previous edition provided you xerox the problems as needed. That saved me $160 this semester.</p>
<p>It likely depends on the class. If one of the core components is textbook problem sets, the current edition will likely be essential.</p>
<p>In my experience, at least at my school, professors will let you know if old editions are okay, and if there are any differences.</p>
<p>Email the professor or ask in person. In many cases a newer edition is little more than a new cover. Page number might differ slightly. Professors usually understand the students’ need to save money and will be willing to help you.</p>
<p>The professor often isn’t going to know. If the library has both editions you could check them out and look through to find the differences. For one of my classes 95% of the problems were the same, I just had to go to the library each week to make sure. For another class, whole sections of the book were completely different.</p>