Stephen F.J. Plowman at the Heraldry Online Blog notes in a post today (February 11, 2011) the livery button of a lady which is for sale on eBay.
And you can find the button itself (at least while it remains on sale) by going to the eBay website and doing a search, as I did, for "livery button". You should be warned, however. They have a bunch of different armorial buttons for sale, and you might find yourself tempted to bid on one, or two, or three, ....
("So I hollered up to her and I said, 'Don't look, Ethel!' But it was too late." Ray Stevens, The Streak)