The cost can be varied from 1800-5000 Indian bucks from shop to shop. However, the content of scenery will be same(obviously that is something that can't be changed.)
There is one named Barefoot Scuba which is very professional. You can find their videos on YouTube .(This is the costly one)

Snorkeling will not be as excited as Scuba. It is cheaper activity there. You can have it in 400 bucks(for 10 Mins) without photography and in 800 bucks(20 mins)with photography. Snorkeling is helpful for people who are unfit for Scuba.