Make this small pouch with just a zipper and a ribbon! With the zipper open, it's just a flat, long thing, but by closing the zipper, it zips itself up to form a pouch. Choose a colorful ribbon for a cute pouch, and (optional) finish the inside with second ribbon for a smooth look.

The idea for this pouch came from this website where they have a short tutorial for a similar pouch in the form of a tetrahedron. I found that a flatter, rectangular pouch is easier to use. But feel free to use this instructable to experiment with a tetrahedron shape!

Step 1: Materials

You'll need:

a zipper (about 50 cm or 20 inch long)
ribbon (same length as zipper)
optional: another ribbon for the inside (same length)
thread

Step 2: The Base

First you'll need to determine how wide you want the base of your zipper pouch to be.

Roll up the zipper as shown in the first image to get an idea of the dimensions of the pouch.
Try adjusting the width of the whole thing such that the zipper ends up halfway at the top (see note in image).
At the bottom, mark with a pin where the zipper first folds (see note in image). Unroll.

Step 3: Sew Base of Pouch

Next, sew the first part of the ribbon to the zipper as follows:

Lay the ribbon along the zipper as shown in the second image. A large part of the zipper will be on the left with no ribbon next to it, and a large part of the ribbon will be on the right with no zipper next to it.
The end of the ribbon should be just left of the pin that you marked in the previous step. This means that the length where zipper and ribbon are touching is precisely the part from the base of the zipper to the pin that marks the first fold, plus some space for folding the ribbon over (which we will do later).
Make sure to leave some extra ribbon left of the pin for finishing off later.
If you want to have a ribbon at the inside as well, lay this under the zipper, matching up with the top ribbon.
Stitch through the edge of the ribbon, attaching the ribbon to the zipper (and if you have one, also the bottom ribbon). Don't stitch all the way to the marking pin, leave a little part unstitched (see image).

Step 4: Curve the Ribbon Around the Zipper Base

The idea of this next step is that the remainder of the ribbon (that in the last step was laid out to the right, not touching the zipper), curves around the base of the zipper. This is best sewn by hand.

Curve the ribbon around the base of the zipper (with the zipper closed) such that the zipper stop is just covered with ribbon.
If you have a ribbon for the inside, curve this along with the top ribbon, hiding the end of the zipper between them.
Secure with pins.
Sew the ribbon(s) to the zipper with small stitches (by hand), until you are well past the curve of the zipper base.

Step 5: Curve the Zipper Around the Ribbon

In this step, the zipper is curved around the end of the ribbon. This curve is at the place marked with a pin at the first step. It is again best sewn by hand.

Fold the raw end of the ribbon under (and if you have a bottom ribbon, fold both raw ends in)
Curve the zipper around the end of the ribbon (or ribbons) and secure with a pin.
Remember the place you marked with a pin at the beginning? It should be right in the middle of you curve. This means the zipper starts curving just a bit right of the pin.
Attach the ribbon(s) to the zipper with small stitches (by hand).
Leave the pin in (see image).

Step 6: Stitch Base of Pouch

After these nasty curves we did in the previous steps, the zipper is now opened, making it much easier to sew straight lines.

Open the zipper
Attach the ribbon(s) to the curved zipper for the base of the pouch (see image for result).
Again, the ribbon(s) AND one half of the zipper now need to curve around the base of the zipper. If necessary, stitch this by hand.

Step 7: Stitch Ribbons to Zipper - the Long Straight (and Easy) Part

With the zipper open, a large part can now be sewn with a machine (or by hand of course), attaching the (straight) ribbon(s) between both sides of the zipper.

Stitch the ribbon(s) to the zipper as shown in the first image.
Stitch until you reach the end of the zipper on one side. Note that there will be quite some length of the zipper and the ribbon left over on the other side (see second and third image)

Step 8: Finish Around End of Zipper

Now close the zipper. See how there's already something like a pouch? In this step the top of the pouch will be finished in a neat way.

After closing the zipper all the way to the end, you will end up with leftover ribbon(s) and the top of the pouch still open (see first image).
Curve the ribbon(s) around the end of the zipper to close the pouch as shown in the second image.
If your zipper is a bit longer than the edge of the rectangle formed by the pouch, this is where you can cheat a little. Just let the ribbon curve over the end of the zipper at the place where you want the zipper to end, and you're fine (see note in image).
Secure the ribbon(s) with pins.
Open the zipper and stitch the ribbon(s) to the zipper.
Finish the end of the ribbon(s) by folding the raw ends under before stitching to the zipper.
The result is something like the third image. You might need some hand stitching to get a nice result around the zipper end.