Actually it is like this.
Let's say your cart value is $125. Then add shipping charges- let's say $50. So total is $175. Now the "import fee deposit" (customs duty) collected will be 28% of $175 and not on $125., which will be around $47. So the total is now $222. Now discount the shipping charge of $50, so you need to pay $172. So $47, is around 38% or so of $125 (the basic price of BDs).
Normally their prices goes up and down like anything (it can go as high as, which more than double). Please refer blu-ray.com for price history. So unless you are in a hurry, look for the most optimum price level for a BD before ordering. Normally the boxsets are cheaper so is the older titles. All "NEW" individual release are priced around $20 normally and goes down as time progresses.
Let me give an example, The Mummy Trilogy is now around $25, which came down to under $15. So if you order at $15, then with customs the landed cost will be $20. Thus 3 movies for INR 1400, not bad. Similarly there are lots of good titles available around $5. So for $125 (plus $50 duty), you can get around 20 titles.
But still it will be more than the 50% offer from Indian sites. That's why you should go for International titles, only if the title is not available in India or the Indian version is censored heavily.