Please note: this is my first instructable.
Step 1: Materials and Pattern
You can either sew the wallet together (which I am doing), or tape it together with packing tape or duct tape or another suitable tape.
This is the pattern, all measurements in inches. No seam allowances are needed.
If this image is unreadable:
the main body is 6 x 7.5
the small flap is 0.75 x 2.5
the large flap is 2.5 x 4.5
Step 2: Construction Step 1: Cut Out Pattern
Cut out the perimeter. Do not cut the flaps off.
Step 3: Construction Step 2: Attach Elastic Band
Fold the flap along the dotted line (about 1/4 inch from the body of the wallet, depending on how many cards you carry) and sew the elastic to the body at the top and bottom of the elastic.
Step 4: Construction Step 3: Change Pocket
Make accordion folds at both sides of the flap. Sew them up. Finally, sew the bottom (you may not want to sew over the accordion folds - I did). The pocket is now complete. OPTIONAL: add a zipper to the top of it.