Whatever you use needs to be natural fibers...cotton, linen, etc. if you're using fiber reactives. They won't work with synthetics. I get Kona cotton at Hancocks...they discount the bolt ends of the 108" wide stuff. (I live near Paducah) All I do is wash it and don't use fabric softener...I've been dyeing for years and never purchased PFD fabric. Overdyeing is a great way to get additional prints or colors and I am always bringing home thrift store stuff for various projects. I buy used white cotton clothing and once they are washed, make perfect tie dye. Old bluejeans are cool overdye and there's always a horrible print that can be turned into something great. Tthe others are right...Dharma is wonderful....I get most of my supplies from them, but do drop a big chunk with Pro chem each year at the quilt show because I appreciate their loyalty to the event.Dharma has tutorials that are really handy. Here's some of my dye projects...a tie dye quilt I made form my niece...an overdyed bluejean Kindle cover and some ice dyed silk scarves.