Lots of good quilting materials available at thrift stores, however I do not go to Goodwill. They are twice the price of all the other thrift stores in our area and no sale days here. Men's cotton shirts, ladies full skirts or dresses with lots of fabric in them can be good buys. Tell your friends you would appreciate any clothing or fabrics they don't want any more. Watch the garage sales in season. They can be a great source. If you attend a church let it be known that you are looking for good used or new fabrics for quilting. You will probably get some stuff you can't use, but sort it and use what you can. You don't have to buy $10 a yard fabric to be a terrific quilter. Check out Craig's list if you have a computer as well as Freecycle.