Half gallon milk or juice carton with plastic cap, rinsed
Craft knife (optional)
Cut open the carton so it lies flat, as shown; put aside the cap for now. Dry the inside with the paper towels. Tape the template on top of the carton so that the top circle lines up with the spout. Mark the outline of the template with a ballpoint pen. Using firm pressure, trace the lower circle and the dotted lines of the template so that they transfer to the carton. (This will score the lines for easier folding.) A ruler will help you mark the straight lines. Cut out the shape from the carton.
Use scissors to cut out the lower circle as marked. (Tip: To make cutting out the circle easier, first make an X with a craft knife.) Use a ruler and a butter knife to further score the fold lines.
Following the fold lines you marked, create an accordion fold on each side of the wallet.