I purchased the scarves for about $2.50 at Dharma Trading. I didn't have a very long advance notice about doing the project and was pleased with how quickly they arrived. I purchased the 8 x 54 inch scarves.
I ironed the scarves, using the silk setting, since they did arrive with creases from being folded. The floral designs on the scarf are made by cutting out shapes from tissue paper, placing the tissue on the scarf, and spritzing with water so that the dye from the tissue is transferred to the scarf. Not all tissue paper bleeds. You might assume that the inexpensive tissue that you can buy at a dollar store would bleed, but that is not always the case. I purchased a packet of Celebrate It. All of the darker colors bled nicely, not so much with the pastels. I also have read that a brand called Spectra will bleed. The water will soak through the scarf, so work on a well protected surface. If you don't like the way an area turns out and the color is pale, you can always soak up excess water with a paper towel and then try again. When you are satisfied with your design and the scarf has dried, use an iron (silk setting) to set the dye.