buying cheap cams like the wansview or foscams may not be your best option as these do not have sufficient resolution to properly ID a thief. Plus the foscams are notoriously unreliable - esp. the wireless variety.
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Login and see the problems others are having with these cameras. A good site to learn from is cam-it.org The Q-See cameras can be gotten at Costco.
The other thing about IP cameras is that you will need something to 'record' the alerts from the cameras. There is a pgm called BlueIris which is excellent for $49 (You are not allowed to view links.
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Login) You obviously will need a pc to run it on. Anything more than a few cameras will require a pc with a pretty decent cpu. Something with multiple cores or hyperthreading works nicely. You won't need a lot of ram 8gb will work, however depending on the amount of activity and the length of time you will be storing the recorded videos does mean a lot of hard drive space. I have two 4tb drives on a dedicated pc running an amd 8-core.
The point is that a lot of planning needs to go into these security systems and not an insignificant amount of $$$
good luck