Posted in questions about PBS:  http://www.paperbackswap.com/forum/topic.php?t=162057

But since y'all are the fantasy experts, I'm cross-posting here with the additional info that this is Mercedes Lackey's Dragon Jousters Series - does it make a diff that I would want either credits for my non-posted books or to trade for the first two Last Herald Mage series (and I'd order the third) on the member's shelf! None are OVERWHELMINGLY popular with 100 person WLs, but still! We Lackey fans love our Misty and forgive her many sins! LOL...

It's my understanding that direct book swaps are not kosher at PBS.  Although boxers may arrange direct swaps for bookshelf items, which would not include WL books. 

What are you calling non-posted books?  Unpostables may be offered for free or a credit, ONLY through the book bazaar thread and NOT through FIFO.  Or are you referring to books not yet on your bookshelf b/c they are wishlisted?

If you wish to offer your books as a set, for postage or other reasons, most genre forums have a thread for offering wishlisted books.  Just post your books on the thread and state you will give priority to members requesting the entire set.  They will need to have the books on their wishlist so you can post direct from there, and bypass FIFO.