Alt text: Meme caption: "When you forget to bring your reusable bags to the grocery store", below is an image of Dexter from Dexter's laboratory weeping as he strokes a picture of the earth, saying "I have failed you!"
Solution? Sewing DIY bags from old clothing.
More reusable and personal than a factory bag, and you already know how to mend it to keep it going. Uses less raw resources than a plastic bag, as it was going to the trash anyways. It's a great beginner sewing project.