Lay out 5 strips of 9 inch pieces of tape sticky side up(slightly overlap strips).
Lay out whatever 6 cards you want to use, in 2 rows of 3, carefully face down on the tape. (note: make sure the cards are facing the way you'd want them to be seen from the outside.) (another note: leave enough space in between cards so that it folds.)
Seal the other side with 5 more strips of tape.
Cut excess tape away from the sides of the cards.
Use 3 inch strips of tape around the sides, bottom, and each side of the top to secure your wallet.
Optional: You can create a pocket for gift cards, credit or debit cards, and anything else you want to hold by cutting another card in half and taping it to the inside of the wallet. You could also cut out a hole where a Pokemon's face is and use that to store your ID.
Now you can easily carry your money in style! You can use any other types of cards, such as Yu Gi Oh!, Magic the Gathering, or Dragon Ball Z to tailor this idea specifically to your interests!