get the cheapest webcam u can find & then get a free webcam program that does motion sencing. I bought my webcam for 20.00cad so thats like 15-17.00usd. very cheap... u can set up the program to save all photos & u can montior it online aswell... All I think u'll need is an extra long wire or an extention cord for the camera. & that might be about 20.00usd... the program I have is called VisionGS PE 1.21.. the newer one is horrible & super buggy, so only use this version. if u can find better, then use that, but u don't need to pay for this one.. go to www.tucows.com & it has lots of free webcam stuff.

To view mine (its dark because its looking into a dark tank & I have the lowest quality on) aqua cam

This is just to give u an idea