Upcycling Different Materials Into Bags

I've learned in one of the fairs that you can sew things other than fabric. This makes the perfect green project - recycling different materials you can find at hone into something useful. I've been trying to use different materials, such as plastic bags, envelops, product packages, etc.
Materials needed: any unwanted plastic bags, strong enough to be sewed, a sewing machine.  * For a step by step instruction for a soil bag, please go to: https://www.instructables.com/id/Upcycling-Plastic-Bags