A layer cake, jelly roll, or charm squares?
(For new quilters: a layer cake is a collection of 10" x 10" squares, jelly rolls are 2.5" x 44" strips, and charms are 5" x 5" squares.)
Mostly these come with about 40 pieces in each set. Is that a good number? Or would you like the option of being able to buy groups of 20 pieces too? (In case 40 is not enough, or too much.)