This is a cute idea, I would like to try this one.
Cloth place mat/pins/cording for handle/thread/scissors/zipper,Velcro,snaps (Optional)
Fold a place mat in half width wise,so that right sides are facing each other.
Pin the ends of the cording to the inside edges near the top of bag. Sew cord to mat to secure in place.
Pin the rest of the open sides together. Stitch together both sides, then remove pins.
Create a gusset bottom by pulling the sides apart and sewing straight across to create a triangle shape.
Flip bag right side out and push out the corners.
The easiest closure option is to leave the top open, but you can also sew a zipper on,add Velcro, or attach snaps.