Question: I want to assemble several cameras, triggered by a single remote. Is this possible?
The trigger doesn't have to be wireless, because the cameras will be very near to each other. The cameras need to be very cheap, because I'll be needing 50 of them.

Answer: 
If cost is a central concern, then you might want to investigate a DIY route. Using a platform such as [Arduino](http://www.adafruit.com/category/17), you can [purchase basic cameras](http://www.adafruit.com/search?q=camera&b=1), and using the Arduino board, trigger them together in a variety of ways...really only your imagination is your limit here. As most of these cameras are very small, it should be easy to pack them together.

I have linked to Adafruit for these items, but there are hundreds of vendors for Arduino or Raspberry Pi products.
This is the product recommended by Chris Breeze and Eric Pare at Xangle amongst others - the Esper Triggerbox <https://www.esperhq.com/product/triggerbox/>

The ESPER TriggerBox is the world’s leading programmable multi-camera shutter release controller. Up to 6 cameras can be connected to each TriggerBox and it allows multiple camera to be fired simultaneously or with programmed sequences and offsets + multiple TriggerBoxes can be linked together to synchronise larger multiple camera setups and they neatly stack together, a bit like LEGO bricks! [![enter image description here](https://i.stack.imgur.com/YFFtf.jpg)](https://i.stack.imgur.com/YFFtf.jpg)