First of all Home Owners should understand benefits of False Ceiling. One of the important benefit which is not well know is good optimise use of Air Conditioning. False ceiling reduces space in ceiling it helps by increasing Air Conditioning performance. Of course I am talking about rooms with too much height. Lets say your office is 10 x 10 sq feet big room, if your false ceiling is 1 feet below actual ceiling, will cut down ( 10 x 10 x 1 ) cubic space. That’s definitely saves your energy bill. Inside residence, living room gives good feeling if it has more height, however in bedroom you may think of reducing height a bit. In Kitchen usually people avoid false ceiling, if you have to have it then make sure Chimney / ventilation is in place.
Second benefit is that it provides insulation layer. If your home roof is exposed to direct sunlight or indirect heat. False ceiling will put in one separation layer to keep heat away to some extent. Keeps your room cooler.
Very basic and economic cost of False Ceiling comes out to Rs. 150 – Rs 200 per sq. ft (square feet) . If you add some creative designs and material quality cost goes up. Designs that gel well with rest of the room.
Also checkout interview of False ceiling contractor to know more practical tips.
Plaster of Paris ( POP ) is being used since long long time. Since last few years, Gypsum boards are used a lot. Previously simple wood was used, now good quality Ply is commonly used.
Other big advantage is instead of putting 1 or more Tube Lights inside your room, you get to use high quality LED lights. LED lights consume less energy and most of them work well for years and years. This way you get indirect light. You can have LED inside your false ceiling in different corners of your home and use light as mush as you need it.