|File this under the "DUH! Why didn't I think of this before?" category:
After buying a large amount of buttons at 60% off, I had the idea to sort them by style/color, put them into snack-sized zip baggies, and into a little 3-drawer plastic storage bin. This way, I won't be hunting for another card of buttons in the right size that I am certain I have ... or trying to match exact styles from the same colors at night under less than ideal lighting situations.
They fit better if you pull them off the card, which also drastically reduces the amount of space needed.