This will show you how to reliably photograph lightning for under 3 dollars.
Step 1: Professional Lightning Photography
So first, buy yourself a disposable camera. I used a 1000 speed "high action" camera (because it was the cheapest at ~$2.30) and the results seem to hint that a slower speed would work better (those that developed were flooded with light) and I'll tell you how it goes.
RESULTS: the picture in the Intro was taken with a 400 speed camera. Worked great, especially since the photo was taken at dusk.
A word of warning: After experimenting with Kodak disposables, I've found they don't work the same way. They use a spring trigger, which doesn't fit the following steps. I'd stick with fujifilm (plus, they are generally cheaper)
Step 2: Open it up
There are clips on the sides and top of the camera that releases the front. Use a coin, screwdriver, scissors, etc. to pop these open and take off the front. Be careful not to pop off the back or bottom, exposing the film.
When you open it, the lens will probably fly out, so don't tell me you haven't been warned.