Thanks for the codes. Keep them coming.
A reminder that eligible books are "non-agency" books, which can be identified by the fact that they have two prices (a "List Price" and "Our Price" on Kobobooks.com), are quite inexpensive, or have a price that does not end in 99 cents. There are exceptions, but those are the rules.
Edit: I haven't used the above codes yet, in case no one else has yet either.