There is a jump in price when you go from regular flash models to IR (InfraRed) models. The IR models do not emit much visible light when the flash goes off. Whether or not a regular flash scares animals is debatable, but for sure the regular flash is very visible to humans. I had one in the woods behind our house and I returned it after a week because my family kept complaining about lightning waking them.
The Bushnell Trophy Cam for $200 is a great all around model.