To make a reusable grocery bag, collect 1 yard of fabric, 1 package of piping, 4 feet of 1-inch webbing and thread. Choose a durable fabric, such as denim.
Mark and cut the fabric for each part of the bag. The body requires a 37-by-14-inch piece of fabric. Cut two 15-by-8-inch pieces for the sides and two 24-inch pieces of webbing for the handles.
Sew piping along the long sides of the 37-inch pieces of fabric. Line up the side pieces with the center markings of the body, pinning together. Clip the body of the bag at the corner of the side. Sew the body and the sides together along the pre-sewn piping.
Use a seam finisher, and press the seams to cover the raw edges after sewing the bag together. Turn down and press the top edge by 1/2 inch all around. Measure 1 inch down, and turn the hem down once more to hide the raw edge. Stitch the hem in place close to the turned-over edge.
Fold and press the webbing in half lengthwise, unfold, and re-fold so that the two edges meet the pressed center line. Press and sew the folded edges. Sew 1/4 inch down from the folded edge, and enclose the raw strap edges using a seam finisher.
Measure 3 inches down from the bag's side seam, and pin the straps in place on either side. Sew the straps in place using a square-shaped seam with an X through it.