I'm trying to get into HDR photography, which usually requires some very long exposure shots. The best way to do this is with a tripod and a shutter release. I got the tripod off Craigslist, but the shuuter release was too expensive for me, so I set off to make my own. This is inspired by this tutorial for a Canon DSLR.
To keep this on the cheap, I kept it minimal. The most expensive item was the hands-free phone kit; on sale for $10. Check the comments. One was found at a dollar store. $1!
(1) Hands-free cell phone kit
IMPORTANT: The DSLRs take a 3/32" stereo plug. See the picture for details.
(2) Momentary buttons (two colors)
(1) Mini micro switch
(1) Enclosure, for me a wonderfully ironic 35mm film canister
Drill & bits
Soldering iron and solder
Wire stripping tools
Mad Skillz (which you have, because you're cool enough to find this)