Step 1: Materials
~Eight 3x5 index cards (seven if you don't want a strap)
~Clear packing tape
~Duct tape (any color; I used silver)
Step 2: Making the back of the wallet
Step 3: The bill folds
Start by placing an index card so that it overlaps with the right-hand index card (the taped up one). Next, place a strip of tape as in picture 2. Fold the edges of the tape over, bottom edge first, in order to secure the card. Use your scissors to trim off extra tape. Cover the index card with horizontal strips of tape that trail off over the right-hand edge, and fold over those edges so that the right side edge is uninterrupted between the original card and the newest one. Make sure that you leave the top edge open, otherwise you won't have a pocket. Repeat this with another index card on the left side, then use two strips of tape that span across both cards to fasten them together. Press down on the middle area (the centimeter bit) so that you end up with two separate bill folds.