This is an easy and cheap wallet that doesn't look too bad if you do it well and it's at least functional if not pretty.
It's also my entry for the Gorilla Glue Contest so it would be nice if you voted for it.
Step 1: Materials
You will need:
A box cutter
Fabric of your choice
A Cardboard Box
The packaging from a 12 pack of soda.
Step 2: Pockets
Make the pockets of the wallet out of the soda carton. I did it by outlining a credit card in pencil and then measuring 1/2 a cm away from the outline on every side except for the top. You should go 1/2 a cm down from the top so that you can get the card out.
Then make small pieces of cardboard and glue them to the edges of the pocket (like in the second picture).
Step 3: The Body
Make 2 cardboard pieces that your pockets fit on. I made four because I was nervous.
Then glue the pockets on to the cardboard pieces, but only put glue on the little cardboard pieces from the previous step, otherwise you won't be able to get your cards in.
Step 4: Assembly
Duct tape the two cardboard pieces from before together, but make sure they are far enough away from each other so that you can open and close them.
Then cut your fabric into a piece slightly bigger than the wallet on all the sides except for the top.
Glue the bottom inch or so of fabric to the bottom edge of the wallet and then fold the fabric up to the top. Fold the ends of the fabric in and glue them to the cardboard.
You should have a pocket between the fabric and the cardboard where you can keep cash.
Step 5: Fin
Your wallet should look like this.
If not better.