Yay! It's my first instructable, please leave comments on what I can do to make this, and future instructables better :). This is a wallet made by two 8.5x11 pieces of whatever fold-able, cut-able, and write on-able piece of material you want. Tyvek would probably be best, but since I do not have any and have not had time to run down to the post office I have made do with paper.

also gift cards are the same size as credit cards in case you don't have a credit card

lastly, I will update the soon to come pictures with pictures of me doing this with tyvek as soon as I can get some.

Step 1: Materials

The materials are pretty simple and everyone probably has them around their house.

1- scissors
2- tape
3- pencil
4- paper, tyvek, paper bag, etc.

optional- a knife or utility blade might be nice, so might a ruler, and an eraser

Step 2: Preparing the Folds

1- First fold hot dog style as if you were making a paper airplane
2- Then place a credit card or gift card inside the fold and let it fall to the left edge but prevent it from falling out.
3- Now, feeling where the edge of the card is, fold the paper valley-style a centimeter or so off from the edge of the card. then unfold everything and remove the card.

Step 3: Cutting

From now on I will call what you see as the top piece of paper the back paper and what you see as the bottom piece of paper the front paper.
1- Lay a dollar bill on the back paper so that the bill's bottom edge is aligned with the horizontal crease. Make a line along the top of the bill. Make a line about a half centimeter above (away from the horizontal fold) the line you just made. you may erase the first line. Make a line parallel to the horizontal fold that goes through the mark you just made. Now cut along the line you just drew to cut off the excess paper.
2- On the front paper do the same as you did with the back paper, but this time above the line will mean toward the horizontal fold, you want to have the front paper to be barely above the height of the shorter end of a credit card.
3- On the front paper you should see a mountain fold, cut all the way along this fold from the edge of the paper to the horizontal crease.
4- Also on the front paper cut a slit about the size of the short side of a credit card that reaches neither the edge of the front paper, nor the horizontal fold. It should be perpendicular to the long horizontal fold. cut this slit about three quarters times the long side of a credit card from the cut you just made.
5- Cut out a piece of paper with the same height as a dollar bill and the same length as two times the long side of a credit card.
6- Finally, cut a window in the front paper about a centimeter from the left edge and a centimeter above the horizontal fold. make it approximately 7x4 centimeters, or whatever you think should be good for showing picture ID.

Step 4: Putting It Mostly Together

1- Align the bottom of the piece of paper you cut in #5 in step 3 with the horizontal fold and the left side of it with the left side of the back paper. Tape all edges except for the top to the back paper and to the bit of the front paper right near the horizontal fold. The cash goes behind this.
2- Fold up the front paper so that it actually becomes the front paper, and tape down all the edges to the back paper
3- Next tape down the right side of the cut that you made in #3 in step 3 to the paper behind the front paper
4- Also tape the right side of the slit made in #4 in step 3 to the paper behind the front paper.
5- Place a card in the slot with the window and a few cards in the second slot and a few dollar bills in the pocket behind the credit cards.
6- Refold the fold made in #3 step 2, you may need to pull the cards in the second slot out a bit.
7- Mark 2 or 3 millimeters off the edge of the credit cards in the second slot
8- Mark 4 centimeters to the right of the mark you just made and cut perpendicular to the horizontal fold so that when the wallet is folded there is about 4.2 centimeters sticking off from the edge of the cards in the second slot.
9- Using scissors or a knife, round out the edges of the 4.2 centimeter protrusion and fold it over. so that you have a more compact rectangle.
10- If you are using paper you should cover the whole outside of the wallet with tape but be careful not to tape anything to anything else, just cover with tape to make it more durable.
11- Finally, cut a 5 centimeter piece of tape and fold over the end so that there is a very short non sticky part, then stick the completely sticky end to the 4 centimeter protrusion and when you fold it over, tape the other end of the tape to the wallet itself so that it won't come apart, you can use the short non sticky tab to open it more easily. Velcro might be preferable but it is more bulky and I didn't have any.