according to this, access codes are only good one semester
http://www.bookstore.mcmaste r.ca/textbooks/access-code-faq.html#3
so how come i see so many listings where people are selling access codes along with the respective textbook? its not like you can buy a used one...
and according to titles, access codes (ie for chem 1e03/1a03) are 50$, so unless you buy a used chem textbook/sol'n guide for less than 55$ (title's price for the package is ~105), you might as well buy new... right?
are the access codes necessary (particularly for chem 1e03/1a03)? is there any way to get them cheaper?