It is a good idea to know where the books for the course are being sold and roughly how much they cost. Check to be sure that what you assume to be true in this regard is in fact the case. You will need to know whether an order has been delayed, whether there are enough books, and whether any of these conditions will affect your ability to follow your plans. This advice also applies to books placed on reserve.
Many instructors use the Seminary Co-op Bookstore for ordering class texts. More detailed information regarding their policies may be found here.