Elizabeth Freeman offers some experiences and rules for buying used books from Californians.
What I dread are the decrepit cardboard boxes or trash bags. Books schlepped in a rippling thirty-gallon plastic bag are not books in reasonable condition; they are books which have become recyclables or a mold hazard. And yet occasionally there are treasures: the first time I ever saw an Armed Services Edition paperback it was in a trash bag. There were fistfuls of them, binding and pages all perfectly intact (despite the former being a single staple and the latter incredibly thin and delicate). I bought them all and watched them sell within days.