5 minutes ago a student emailed me this question:
Is it really necessary to buy the whole book again?
or is there a code I can buy on the internet?
That was the entire text of the email. Note the lack of salutation, punctuation, capitalisation, etc. I have an email policy, as every student I teach knows. Please follow it, because from now on I won't be replying to poorly worded emails.
Also, in answer to their question, yes, I really, really do think it's a good idea in week 4 of term to buy the custom text book and the aplia key to get 50% of your grade.