Or use scraps. Just about any fabric will work for crocheting rag rugs. Lightweight fabric will not produce as sturdy a rug as cotton and cotton blend fabric. The fabric color is the most important thing to remember. Patterns of the fabric will not show in the rug, only the colors.
Color is important in the finished look of the rug.
The best and least expensive way to use fabric in making Crocheted Rag Rugs is to use fabric mill end rolls. The best and fastest way without having to invest in expensive cutting machines to split your fabric is to have two people involved. It only takes about 10 minutes to split a 10 lb roll of fabric. Use a rotary cutter to cut the fabric to the desired width. Cut as many layers of fabric as you feel comfortable cutting at one time.