Vanessa from Crafty Gemini shares a video tutorial on her blog showing how to make a simple drawstring backpack from t-shirt knit. She used knit yardage for the one she made, but you could get all the fabric you need from a repurposed t-shirt. (Look for a heavier t-shirt, since you’ll be using this to carry stuff around.) Go to her video tutorial.
[photo from Crafty Gemini]