This is a handy trip for when you're traveling or to have in your bag just in case of emergencies. All you need is an old chapstick container with a lid. Wash it out before using it and ensure it's completely dry. You can use a cotton bud to dry the edge of the rims. Once the container is dry, roll up a few $10 notes and stick them inside.
It's inconspicuous, so you'll be the only one who knows it's there. So keep it in your handbag, car, pocket, or wherever else you think it could be helpful. Then, if anything goes wrong, you'll always have a bit of backup money on hand.