I was wondering since paperbacks I have bought before my arthritis got bad in my hands if audio books can be swapped, perhaps 2 or 3 books for one audio book. Some of them are new. Audio books are expensive.

It is allowed to swap audio books.  I presume you mean that you will be willing to send 2 or 3 paperbacks for one audio book, not the other way around.  I'm sure some swappers would be happy with this but I'm not sure how you would get the message to them unless they have a forum profile and you can PM them.

There are quite a few audio books already listed on the site - there is a filter for them at the top of the Library pages:

The following books are available in All Fiction (56017 titles):

Filter by: None | Audiobooks

Usually people just swap them on a 1 for 1 basis with ordinary books or other audiobooks, but if you want to offer more than one book in return, you could put a comment in the description for your books saying that you're happy to offer 2 in return for an audiobook, then you can sort out which other book to send via PM - just don't forget to remove the 2nd book from your list!