That, of course, would be the cheapest route. The next option, which I kinda like anyway, given the places I am likely to drag my camera, is a cheap SLR, like the Zenit B or Zenit E. No batteries, completely manual. The only difference between these two is that the Zenit E has a light meter. The lack of electronics is a plus in this case, since it means no electronics to fail. The downside is, you gotta think about your exposure, yourself (another up-side in my book). Given that you can get one on eBay for $20-40, delivered, it's pretty hard to beat. If it gets wet, it will dry and be good as new. If it gets dirty, you shouldn't have opened it in the dirt, but, give it a good cleaning and it is good as new. If it gets stolen, well, darn. You're out $20-40, and the thief has a camera he probably won't know how to use. 
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Justin, Julie and the meangerie...
(Bobbing igs, snapping macklots, exploring ball, hungry kings, hyper grey rat, quacking tribs, hissing roaches, wriggling worms & chirping crickets)
Vermont Herpetological Society Online
www.vermontherps.org