I doubt you would only use a digital camera one time --once you start using one you will most likely fall in love with it. Small, compact, and you can just delete the pics you don't like. I find that I take a LOT more pics now that I have a digital camera.

I am on my second Sony CyberShot. My first one I had no problems but the newer ones were smaller and lighter so I upgraded and gifted away the first one. I have heard good things about the Canon Elf also, and know one producer that uses Elfs exclusively for all photo shoots.

That being said, I do see older models of digital cameras [under 4 MegaPixels] on www.craigslist.com for low prices.
If that is still too much, you can now buy disposable digital cameras in drugstores. I have seen them in both Walgreens and CVS for less than $40. I would go with a used name brand digital camera. You wont just use it once!!