Just a few thoughts:
For those of you that want to do 9 sets, it's understandable if you want all your charms different. But if you are going for a quilt that is scrappy-- over the size of a bed quilt, it's hardly noticeable if there are two charms the same here and there, when most of the charms are different.
Plus, there are lots and lots of block patterns that use eight 2 1/2" candies, or four triangles. You can cut two charms into candies or triangles, so it can be very useful to have two charms of the same print if you plan to make blocks.
Plus, it's a better deal for the cost of postage to go to the top limit of charms.