Students nowadays are more luckier considering that majority of course/module handouts are given-out by the lecturers and more reference books are readily available in the library. Of course, with internet/online connection, it is much easier and manageable to do further readings or to do the assignments.
With the introduction of e-reading devices (like the Amazon Kindle), some of these academic books are now accessible to everyone - free of charge. I chose some of them (as shown above) that I think more helpful for students and teachers or even for those people (like me) who want to review some of the basic theories in geometry, trigonometry, earth science and chemistry.
NOTE: These ebooks are freebies in Amazon.com and Amazon.co.uk for both UK and US regions at the time of posting. It might NOT be free in other regions but normally available for discounted prices.