Duct tape wallets are non-optimal. The nature of the adhesive used on duct tape results in a wallet that will slowly slide apart based on the forces input to the wallet by your ass. After a year or so, depending on the ambient temperature of your location, the wallet will be falling apart and you will be building a new one. Besides, who needs all those pockets, a full length cash slot or other "wallet" features? In today's modern, RFID, credit-ready, cash-poor society a money clip with credit card and drivers license storage is truly the best wallet you will ever need. Any more storage and you will tempted to store receipts, ATM slips, business cards, and other sundry items in the wallet until you have a full blown case of "Costanza Wallet".
Enter the Innertube Wallet. As a Maker, geek, or otherwise shunned cheapskate, you doubtless have numerous blown bicycle innertubes, a few sheets of rusty 22 gauge steel, and any number of DOA hard disks and their attendant magnets. With such materials and a boundless enthusiasm for turning interminably stored junk into stuff you don't need, I present the bitchin' innertube wallet to solve all your wallety needs.
Step 1: Assemble your materials
1. Innertube. I recommend a mountain bike tube rated in the 2.1 to 2.6 inch range. Patches are optional but add a nice touch. You will need about 6-8 inches of innertube.
2. Thin steel sheet. I had a spot welded piece of 22 gauge sheet steel sitting around that was magnetic, and easily cut with my available snips. Rust is optional but gives street cred.
3. Metal snips. My brother-in-law has been borrowing my legitimate tin snips for about six months so I had to use my "super scissors" (pictured) which put the hurt on them. You should use real snips designed for steel. Since I had about 25 minutes to complete the project, I had to make due.
4. A magnet. I used a rare earth magnet from a broken 2GB Caviar HDD that I had sitting around. You will need something stronger than a fridge magnet, but the steel sheets will shield your credit cards from the super strong rare earth magnet for the most part.
5. Rubber cement. I used a bicycle tube patch kit to glue closed the assembled wallet.
6. Lastly you need some kind of file or sandpaper to smooth the steel pieces you will cut.