My friend recently outfitted his homeroom (we are in high school) with a minifridge, and is letting people take drinks. The problem is that some people are taking drinks faster then he wants to stock it. We are considering getting a low cost security camera, to attempt to enforce a limit. Can any of the security experts out there recommend something? Thanks.
If you get a security camera you need to have some way of viewing it. You may consider a USB webcam and saving images to disk.
So how do you intend to enforce the limit?
There are motion activated Camcorders that will probably work nicely.
Couldn’t he spend the money intended for cameras on, ummm, more beer? 
I see England’s schools are light years ahead of ours. 
I had one of those in college, stocked with cheap, cold beer. I took a trip to the local hardware store and bough the hardware necessary to put a pad lock on. Then nobody stole my beer.
Wait a minute. The OP said high school. Unless these folks repeated 3rd grade five times, they’re protecting soda. :smack:
Move along, nothing to see here.
There are small 'for Pay" dispensers. Basically, tiny refridgerator/vending machines.
Form a club, & refund money at the end of the month. But set up a rule that says: “If the claimed # of sodas taken does not match the ammount of money in the machine, the Club Founder refunds no money. If you cheat, everybody loses sodas at cost.”
The company I work for sells some security cameras. Unfortunately for this thread, we don’t sell Wal-Mart stuff. We install high-end cameras on ships, hospitals, government buildings, mini-storages, etc. We installed a great ]url=“http://news.sel.sony.com/digitalimages/photo?photo_id=161671”]Sony PTZ camera (SNC-RZ30N) on a building in downtown Bellingham that has some really impressive performance. There’s a developer who owns property here, but he’s not allowed into the country because the Border Patrol found a joint in his car yonks ago. He had the camera installed so that he can keep an eye on construction from his home in Canada. Anyone who knows tha IP address can play with it. (Of course, I’m not going to post it. It’s the guy’s private property.) It’s really cool; and for about five kilobucks, installed, it should be!
Non-PTZ cameras are cheaper, of course. Still, they’re a few hundred dollars each. Non-network cameras require a recording device. I just saw a four-channel digital video recorder for $399. A Pelco unit can go for $8,000 or more.
As I said, we don’t sell “consumer” gear. The applications for which we install demand more robust equipment. I haven’t checked the price of consumer webcams, but I’ve heard they’re really cheap. Still, how cheap is “cheap”? Maybe your friend can say “This free beer thing just isn’t working out. Please do not take any more beer. Thanks.”