The small size should fit most versions of the Kindle, as well as many other e-readers of approximately 5” by 7.5”. This cover is meant to stretch width wise quite a bit, and shrinks a little length wise.

Color A: 1 Valley Yarns Greenfield spring green (50g/88 yards) or 1 Blue Sky Alpacas Skinny Dyed Cotton color #318 (65g/150 yards)
Color B: 1 Louet Merlin Worsted black (100g/156 yards)

You can get at least 2, if not 3 covers out of one skein of Blue Sky Skinny Cotton, and probably 2 from Valley Yarns Greenfield. Very little yardage of the Louet Merlin Worsted is used, so you can make several covers at least from one skein. I was able to make 3, and had enough for at least one more. For the Kindle DX size, 1 skein each of color A and B is enough.