This may not be the prettiest diy stylus on Instructables but at least it actually WORKS...it's pretty simple and easy. Super cheap as well.
Step 1: Materials
-a battery (I used an AA)
-candy wrapper (optional if you don't want the battery scratching your screen)
-rubber band or something to hold the wrapper to the battery (optional as well)
Step 2: Put Together
Both ends of the battery work but I think the negative end works better. Wrap the wrapper(s) around that end and secure it with the band.
Step 3: And Done!
Now you have an awkward looking decent stylus!