Directions for a billfold:
I used a poly-cotton broadcloth for the outside and pockets and a poly lining (to reduce thickness) for the inner long piece. Binding is 5/8" nylon or poly satin ribbon. On mine I stitched a velcro strip about 2 1/2" long near one end of the outside of the outer piece and a 3/4" piece near the other end, to keep the billfold closed in my purse. Left this off of DH's. The first time I made these I also made one for our son as we all wanted a thin billfold. We find these last several years although the corners of DH's get folded and bent from putting it in his hip pocket.
I am in the USA so used a dollar bill for my initial measurement. These are typical one-fold billfolds.
Outside piece: add 1 3/4" the long way, 3/4" the short way. Inside piece: same long dimension, 1/4" less the short one. Pockets: 2 pockets each 1/8" shorter than half the long dimension of the outside, 1 pocket with the middle end angled 1" less to 1 1/4" less than these two.
Bind center ends of the pockets, top edge of outside piece. Stitch pockets to inside long piece in a 1/4" seam, placing the shorter one on top of one of the longer ones. Bind top of inner section. Stitch inner and outer together, ends and bottom, in a 1/4" seam.
Bind end, bottom, end, mitering the corners and turning in the ends of the binding at the top corners. Topstitch the binding ends.
If this isn't clear, ask questions. I thought I had written this up but couldn't find it so looked at mine and went at it. Will save it this time!
Jean