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
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
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.
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.