My bookshelf is quite empty right now.  Is there anyway to offer credits in Box of Books in addition to what is on my shelf?

If you were going to offer credits than why not just order the books you want? 

But no-the perpose of BOB is to trade books for books without using credits.

I rarely have more than 30 books posted and I still do BOB trades pretty regularly.

ETA: If you have credits you want to use: have you tried looking in the book bazaar for some book deals? You might find someone offering 2 for 1 or 3 for 1 with a few books you want.  Then after you read them you can use them to beef up your shelf.

If your intention was to get all the books from a specific person, you can order your first book while ON their shelf (make sure their name is at the top of the page when you click "order this book" and then use the "Order More From This Member" button that will be in the upper right portion of the page, then order the rest of the books you want from them.

This effectively creates the same scenario as a box without books on yourside. Sounds like a strange way of putting it, but it is a true statement!