I volunteer in a charity book and music shop. We sell some of the donations online on our main website.
The fiction books are usually in perfect condition and sell well. We used to throw stuff out - but only items that would never sell or were in poor condition. These days it is recycled, passed on to other branches. We try to minimise what is binned.
We have one part-time manager and the rest of us are volunteers.
http://www.oxfam.org.uk/shop