You could always use the search function...
Learn to knit or crochet.
Re-create a paper grocery sack.
Roadkill-skin it indian style so you can use the head as a lid : )
Hobo bindle (tie the ends of a square of cloth together).
Roll up stuff in a blanket and tie the ends, extra points to use only one rope and have a handle.
Pillow case, or roadkill pillow.
Cut 1/2 the tread off a tire, leaving the side sections for a handle.
An old shoe.
One leg of a pair of pants.
Sew a t-shirt shut, or just tie the arms together tight.
This seams very open ended. Care to put some limits on it?
search online what was used for bags in japanese tradition
they usually come up with cool stuff
Woven paper strips
Woven cloth strips
Metal (cut open aluminum cans)
Human skin (how you get it is your problem)