Hardly origami, but is made from a single piece of paper with no cuts and no glue or tape.
Step 1: You'll Need
a single piece of A3 paper and about thirty seconds. If you can't find a scrap piece of A3, tape two A4s together. Or if I'm talking gibberish, just a piece of paper about 30cm x 40cm.
Step 2: Fold It Here and There
Fold it in half, and then in half again vertically. Open it out so you have four rectangles.
The first rectangle is the back of the wallet so leave it as it is. The second is the back of the first pocket, so make a fold about three quarters of the way along it, and fold it again where it now meets the bottom of the first rectangle.
Fold it back on itself about half way up the original rectangle, and back on itself, and then the last bit should reach about a quarter of the way.
Confused? Just follow the pictures, kay?
Step 3: Round That Fold
On the largest bit, you need to make the fold more rounded, otherwise the large amounts of cash you carry won't fit snugly. To do this, just make an extra fold about a millimetre away on each side of it.
Step 4: Close the Wallet
Make two folds to turn it into an actual wallet. One to separate the two sections, the other to serve as a flap o keep it closed.
Might help if you look at an actual wallet, for dimensions.
Tuck the "flap" into the main cash area to keep it closed. I was gonna design a proper flap, but thought it might be beneficial to mow the lawn.
Once again your folds need to be pretty rounded if you don't want the wallet to skew.
Step 5: To Close
Fill it with cash and cards and the like. There's no coin pocket because my mum said "real men don't keep coins in their wallets." And after one glance at the competition's entrants so far, there's absolutely no hope of this design winning, so I may as well give up. Whatever.
It would be cool though to print a nice design on the paper first. I'd do that, but I don't have an A3 printer handy. Pity.