Goodwill doesn't seem to carry alot of Fabric but I have found alot at Salvation Army, Church Thrift Stores,
but at Goodwill according to Bonnie Hunter you buy the XXL or so Shirts take off the cuffs,collar,pockets,throw them away than cut off the sleeves,by the time your done you could have about 2yds or more of fabric,Im going to give it a try