If you don't want to buy a certain book (e.g. because you only need it for one assignment), you can also borrow one from the ConcepT library (for free obviously).
ConcepT has two different libraries.
The main library is filled by the university library (UB). Each quartile, they (are supposed to) send one edition of all necessary books during that quartile to ConcepT, in case it happens that the necessary books change from previous years. Therefore, this library is quite up to date.
The second library is filled with (old) books that were gifted to ConcepT by its members. This library is ideal if you miss just that one piece of information for your assignment, or are interested in a certain subject and want some further theory about it.
Both libraries are in front of ConcepT in a bookcase, at the Hans Kampingplein. If you are in search for a certain book or a certain subject, come by and take a look. But keep in mind, we only have so many in stock.
If you want to borrow a book from either of the libraries, ask someone from the Board (they have the keys to the libraries) and they will be happy to help you.