Glasses used for viewing images displayed on a 3D TV or 3D video projector screen are of two types:
Passive Polarized glasses that look and wear much like sunglasses. They usually have enough front space to place over existing eyeglasses for those than need to. These type of glasses are inexpensive to manufacture and can range in price from $5 to $25 for each pair depending on the frame style (rigid vs flexible, plastic vs metal).
Active Shutter glasses, which are slightly bulky, since they have batteries and a transmitter that synchs the rapidly moving shutters for each eye with the onscreen display rate. These type of glasses are also more expensive than passive polarized glasses, ranging in price from $75 to $150 depending on the manufacturer.