Basically you have 2 options:
Hand-held 3D scanners (cost at least $300): Sense 3D scanner, Structure.io, Go!SCAN, Fuel3D. Should work out-of-the-box.
USB depth sensors (difficult to find < $100). These have a few limitations:
All don't come with an SDK that creates high quality polygon models from 3D pointcloud. You'll end up coding.
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It will be hard to find a stereo camera for < 100USD. Still, you can have a look on Microsoft Kinect and Asus Xtion PRO LIVE.
There is no such stereo camera with a wireless video transmission in the market however you can make one using IEEE 802.11 transmission bands.