I have an unpostable copy of a book, with an ISBN.  It is on someone's WL with no ISBN.  Can I post this in the Book Bazaar for a credit?

I could be wrong but... If the copy you have is unpostable then it doesn't matter if it's on someone's WL or not, even if the ISBN matched.  It's unpostable, so you're not depriving anyone in the FIFO if you post it over in the BB for a credit.

You can offer it in the book bazzar and if someone is wants then you can post it to them.  But they have to be made aware of the damage before hand and make the decision if they want it bad enough to spend a credit on it.  I would put my version on my RL and see how many copies of it there are. If there's a bunch of copies posted already then this person probably really wants that WL one (maybe for the cover) or they aren't active anymore.  No one's going to pay a credit for an unpostable copy of a book that has other copies available to order.  But they might for a book that's not available.

That was my understanding too..you can do it in BB.

Yes, you can do it in the BB.  Just describe the damage to the book and let people know you want a credit for it.  I bet there's probably a thread for unpostable WL books over there where you can do that.

You can offer unpostable books in the Bazaar for a credit. If your ISBN is available, then its not too likely that someone would pay a credit for an unpostable one.

The WLs for non-ISBN books don't really mean a lot. I think they are often left over from someone WLing every version of a book they want, and the system not seeing it as a similar book so it doesn't remove that one when they get a different version.