720P HD Mini Spy Glasses Hidden Camera Eyewear DVR Camcorder
One of the best hidden camera gadgets. you can use these spy glasses to record videos without getting noticed, you can use it as a camcorder without any mess of holding camera. The quality of the camera may not be that good but its still an amazing gadget because of its design and concept under this price range. you could insert micro SD card and its rechargeable.
IMPORTANT: Use it carefully keeping in mind the legal concerns and do not use it where cameras are prohibited and also respect everyone's privacy.