I have used two kinds: Printed Treasures sells one that you can print on the special fabric, peel the backing and press onto something. The quality of the print is good but is too stiff for quilting. The other kind prints directly on fabric with no glue and you can sew onto a quilt. Is really soft and easy to use and the quality of the print is very good. You just have to make sure the you increase the saturation of the print because the fabric tends to absorb more of the ink than paper does. They are both the size of computer printer and 5 sheets sell for about $18.
Maria