|Unlock Forum posting with Annual Membership.|
There is a thread in the Book Bazaar where you can list it.
You can offer it unofficially, without actually posting it into the system, to another member who would be willing to give you a credit for it.
Or, you can also offer it as a freebie/deal with another order from your shelf.
But ARCS are definitely unpostable. Many members do want them though or don't mind reading an ARC.
ARC, stands for Advance Reading Copy. As such, the book may not have received it's final edit(s) when the ARC is published and may experience substantial changes. The important idea here, is the 'final edit' part.
Which is why free promotional books and give-away editions (which also are often labeled 'not for resale) are postable...because these editions are the final version. Not For Resale only applies to people (such as book reviewers) and venders that have a written contract with the publisher and is not binding on anyone else that may acquire the book later down the line.
As already mentioned, ARC's may be posted in the book bazaar...you can even ask for a credit to cover postage if you like. Just make sure you clearly state the book is an ARC and use the "post to a friend" feature instead of the main FIFO option.