Here is a basic tutorial on how to make a simple purse, clutch or bag, with few materials and a zipper.
This isn't extremely fancy, you could do this to teach young girls how to make their own purses, or zipper bags.

Step 1: Materials

I used recycled materials from old scraps (the black sides) and an old torn shopping bag (the white insides, tougher) and a zipper.

Mine has the following measurements :
4 rectangles of 20cm x 15 cm (7.8 inches x 6 inches) and a 6 inch zipper.
2 white, for the inside and 2 black for the outside.

You can do this whatever size you want, if you want it smaller, do so, and it would also fit a phone, it could be a simple wallet, or a tablet case. Whatever you chose to cover or put in it.

Step 2: Adding the Zipper to the Fabric

I started by adding the zipper to the "top" of my clutch / bag. IT's easier to start with this step because it will look cleaner and it's harder to add it (not to show) at the end.

This is where we're making a sandwich of fabrics and zipper.
I call "right side" the one where there would be a pattern on your fabric, and "wrong side" the one on the back.
So:
Black right side up + zipper right side down + white right side down.
Do the same for the other side of the zipper.

When you turn these 4 sides, you will have 2 black sides on the right side of the zipper, this will be your outside purse, and 2 white sides down, the inside of the purse.

I'm hoping the pictures will be self explanatory.

Step 3: Sew All the Sides Together

We're now taking all the sides and folding them together so that our insides are out towards you, and the (patterend) outsides and zipper are in.

Sew along the margins, mine is by hand but i'm sure you'll do a fabulous job on the sewing machine. Leave about 1.5 cm seam border.

I used a lighter to "burn" my edges a bit so that the margins don't come undone. If you use a plastified type material that easily comes undone, either do this if you're in a rush, or use that closed wide stitch thing (i forget what it's called :/ )

Step 4: Turn It Inside Out and Use Proudly

We're done, now turn the purse inside out and you're good to go.

This is the easiest way to make a clutch, purse, wallet if you'd like, or any other kind of cover , holder, depending on the size you make it.

I hope you enjoyed this and tell me what you thing, show me pictures of the ones you made. Don't be shy :D