Some well-established consignment shops have their rules listed on a website. For example, the one I frequent has the following policies:
-- you must bring in at least ten pieces
-- they cannot have any imperfections, and must be clean, not terribly wrinkled, and not on hangers
-- they must be from a certain range of labels (they are lenient about this and will take anything nice, but in general they don't want things from lower-end retailers)
-- no bridesmaid dresses, and if it's cutting-edge fashionable, it must be from a recent season
-- it must be appropriate to the time of year.
In this shop, the counter staff reviews what you bring in and tells you what they will take. A manager later prices everything and they send a "contract" by mail telling you what price they will list on each piece. They keep it on the floor for 60 days; at the end of that time, you either get 40% of what's sold, or you have the choice of picking up what didn't sell or donating it to charity.
I'm think they're unusually well organized, but these policies are probably similar to what you would find in many places. I don't know if it's typical to set a minimum number of pieces; I guess that saves them from having to cut a lot of tiny checks for people who brought in three items.
I hope this helps!
