A very easy way to put a zipper in a garment is the sew the seam together with long stitches. iron the seam open. Lay the zipper on the seam with the teeth going straight in the center. Pin or glue the zipper in place. Sew down one side of the zipper across the bottom and up the other side. Use your seam ripper and open the seam. You won't be able to get as close as with a zipper foot, but I have sewn them in this way with a regular foot and they looked ok.