You could get books at the LS Bookstore, University Press (in Bellarmine) or the bookstores in Katipunan like National and Mindmovers (behind Mercury Drugstore). Or you can try the DSWS in MVP. Some orgs also have book lending services. :)
For books which are published by the Office of Research and Publications (ORP) such as Precalculus for Math 18, I think you can only get them from the LS Bookstore and the ORP itself (Located at 2nd floor Gonzaga, it's near the 2nd floor of the Cafeteria). Kung wala na sa LS Bookstore and you really need it already, you can also try buying from the ORP directly.
