Yes iphones are the cheapest there,other phones are costlier than India.
iphone 4S unlocked 16GB will cost you under 35k.Check the prices
here(1HK$=6.5Rs approx)
These prices are of Apple store only as you can see so get it from Apple store only and not from local market
Not only iphones but all the apple products are the cheapest in HK worldwide.
Apart from that that Galaxy R and S2 are two different phones.R costs 19-20k where as S2 costs somewhere around 28-29k or may be lil cheap as I m not aware of the exact local market price of S2.And iphone 4S is totally different and its a killer deal if you get it for under 35k.
If you are looking for a phone in India then I would suggest you to have a look at HTC Sensation XE and Samsung Note