Yes yes! I can’t think of a better way to save very easily on daily packaging than by making a bag for your lunch. Bringing your lunch with you cuts down on disposable lunch trays, containers, etc you might use at work or school, and it’s also usually much healthier for you to eat food you bring rather than whatever you can find for purchase. And hey, cheaper for you to boot! It’s win-win-win.
Don’t worry if you don’t have the “right” fabric for this project. Just use what you have, or use any old bag in the end. Just pack a lunch and then step 2, profit!