This is an origami wallet. It's small, sleek and simple AND you can write on it(because it's made of paper). However, it's not very practical for use with actual money; I suggest using it for transportation, business, gift, or any other kind of card. To make one, you need a piece of 9x9 paper and about 2 minutes.
Step 1: Paper Preparation.
If you already have a piece of 9x9 inch paper, then you can skip this. If not, get a regular piece of rectangular paper (preferably rather heavy paper, for durability), fold over the edge(but try not to crease it much) to form a perfect triangle, and trim off the excess(and don't you dare let that extra bit of paper go to waste. Nah-ah! Find a way to use it), leaving a folded over square. Unfold.