A simple instructable for making a slim and simple wallet that can easily be mailed (posted) back home to it's owner.

Gather materials
Step 2: Print the envelope
Step 3: Add postage
Step 4: Strengthen
Step 5: Transfer
Finishing Touches

(Not endorsed by Australian Post.. but should be)

Step 1: Gather Materials

What you'll need:
- At least one 145 x 90 mm envelope
- One 145 x 90 mm piece of cardboard
...or One 4x6 photo and trimming tools
- Printer
...or Writing utensil
- Stamps
...or Authorized metering device with appropriate funds available

Optional:
- Double sided tape
- Artistic talent
- Camera to document the event
- Money

Step 2: Print the Envelope..

If you're going with the old school method (Pen already in motion) you can skip this step.

I used OpenOffice.org to design and print my envelopes. This allows me to input the custom size of my envelopes and easily format my envelope with logos and lovely fonts. I would recommend a clear font to make it easy for our friends (sorters) at the Post office. Be sure to leave plenty of room for the stamps and leave clear the clear zones.

You won't really need a return address, so feel free to use that space for logos and embelishments.

Step 3: Add Postage..

In Australia, one $0.50 stamp will get a regular letter to it's destination. I'd rather not risk it, however and put enough for a large letter. This ensures that if I get a little carried away and overfill my wallet with business cards and rubbish or win the lottery and run out of room underneath my matress, the finder can still post it with confidence (if he/she can still manage to seal it and fit it in the post box).

If you have a postage meter handy, this can actually be a better alternative. With printed postage, there's less chance of someone just peeling off your stamps when they dump your wallet. Granted, I'm not aware of too many pickpockets that would snitch just for the stamps. I suppose a few out there could be collectors, or have a compulsion to write a letter to mom. In that case, just chalk it up to moral rehabilitation.

Step 4: Strengthen..

Prepare a piece of thin cardboard (non-corrugated) or 4x6 photo:
- Cut to fit inside envelope
- Crease and fold cardboard / photo down the center

..and insert under behind the envelope flap. Fold down the flap to keep the cardboard in place and fold the envelope in half at the cardboard crease. Now you have a potential wallet. Assuming you have two cards and some bills this may be sufficient for your monotary storage needs. If you have a very full wallet, you may need a bit more tweaking. Suggestions and tweaks will be available in the final step.

Step 5: Load It Up..

You're now ready to load up your boomerang wallet and wear it with confidence.

Disclaimer: Boomerang wallets are not for throwing.

Step 6: Finishing Touches

Some suggestions:
- You can give the wallet a little more character by printing on the inside (back of the envelope). Perhaps printing howto style cartoon instructions for how the finder should post the envelope.
- Add a dot of double sided tape to keep your cards stationary or to create a closure.
- Waterproof the envelope with clear packing tape.
- Add 2 creases and accordian fold the hinge to accomodate bulkier contents.

Coming soon... the Wallet-Boomerang!! (a creative way to chuck your old wallet)