This is a simple duct tape cover for a "candy bar" style phone, like my Motorola L6 SLVR.
It has a liner to keep the phone from getting scummy from the adhesives in the duct tape and a flap on the back to protect the lens of the integrated camera.
Step 1: List of materials.
2. Scotch Tape
4. Although it's not in the picture, a ruler. Not so much for measurements, but to help tuck the tape inside the case. (You'll see what I mean later.)
5. Lining material. I used the thin sheet packing foam that came in the box with a keyboard we ordered at work. You could use anything that won't scratch your phone. (Plastic bag, Tyvek envelope, etc)
6. Phone, to use as a template.
Step 2: Wrap the phone in the liner material.
2. To make it easier to remove the phone from the finished case, I aligned the top edge of the material so that it was just below the Motorola logo on the front of the phone.
3. Tightly wrap the phone so that the right and left sides of the liner overlap in the back. Tape in place with scotch tape.
4. Fold the remaining material at the bottom of the phone and tape in place. (For my phone I decided to follow the rounded edge at the bottom. I guess it depends on the phone, but I wonder if a boxed end would have worked better.)
Step 3: Start covering with duct tape.
This left the a little bit of the liner exposed at the bottom of the phone. Which we'll take care of in the next step.