I have completed my first year here and didn’t get bad marks in 1st and 2nd semester. I and any of my friends did not require to buy any books. We studied from library books. Some books which we needed for long term use, we read them through PDFs. Not because library do not issue for a long term, but because we needed to underline and highlight things in them.
IIT Patna has a dedicated website from which we can download important books and software.