While this may not be the prettiest iPhone stylus. It's simple to make, inexpensive and it works.
Two things have be understood before we begin. These things will help understand what aspects must be present in order for a stylus to work on an iPhone screen.
First, the stylus must be made of a conductive material. Your hand/fingers must be touching the metal on the stylus in order for the static electricity to reach the iPhone screen.
And secondly the end of the stylus (that touches the screen) has to be at least a quarter of an inch in diameter. This is because the screen is designed to work with your finger tip.
Now I'll show you one of the many ways you can make your own iPhone stylus.
This stylus will be made almost entirely out of a single mechanical pencil. When searching for one look for these features.
The tip must be made of metal and have a long "needle" on the end (where the lead comes out).
It must have a metal clip that can slide up and down the pencil.
Slide the clip down so that the end of the clip makes contact with the metal on the tip of the pencil.
Remove the eraser.
Cover the eraser with aluminum foil. Make sure it's completely enclosed and one end is smoothed out. I smooth it by tapping it on a tabletop.
Now stick the aluminum covered eraser on the end of the pencil by puncturing it with the "needle" on the tip of the pencil.
To use make sure your finger is in contact with the metal clip. You might have to press down on it a little to make sure the entire eraser surface makes contact.
There you have it. May not be as good as the $40 ones but it works. It's made me a better player of the "Draw Something"app game anyway. :) Enjoy!