Where would you recommend one look for books when they don't have a collection? 

Tony - For cheap books, check out local thrift shops. Also, many libraries offer book sales throughout the year where you can pick up great books for little money.  The last one I went to, each brown bag full of books cost only $5.

I love this.  I've also used a single book to great effect in doing a minimal staging of a vacant home.  A coffee cup on a small tray, placed on a window seat with a throw beside it, and a hardback book turned upside down, open, on top of the throw, as if it had just been set aside while the reader stepped out the adjoining door into the garden, made a dramatic impression in a master suite that had no furniture in it at all.  Everyone from buyers to inspectors commented on how they walked into that room and felt like they could live in it. 

Tricia - Exactly - while we need to make our listings look perfect, we can't forget that we also need to make it look like a place to live.