If you want to be able to watch your Craftsy classes, the Kindle "readers" will not work. You would need a color device such as the Kindle fire, or a different type of color tablet, such as the iPad, iPad mini, etc.
I use my Pandigital 8" tablet to watch Craftsy videos. I can also watch them on my iPod, but they are oh-so-teeny-tiny on that little screen, it's hardly worth it!!