I recently discovered spoonflower in my quest to find lovely fabric at reasonable prices, and I am so excited cause not only they print your creations but there are also big contests almost on a weekly basis.
All fabrics are natural - cotton, organic cotton, silk - I already received swatches and they feel very nice to the touch. Not actually cheap, but quite affordable when you want to see your own designs printed, right?
You even don't need to know the ways of designing or editing programs, all it takes is creativity and the will to have some fun, as you can see in the following video:
Yay or nay?