I would totally disagree with this. Even with cheap prices, you cant scale that much with a profit. Also about india, in almost 99.99% games the prices are hyper inflated when you convert them into local currency. I have checked it myself.
This is only possible by 2 ways-
1. They buy in game goods for your account using stolen credit cards, hacked accounts, etc. There are thousands of such people on the internet who sell cheap rss for every major game.
2. There was something a few years ago which I dont know much about. It was only for Chinese I guess, but if you connected your game account to whatever-it-was, you could swap the real currency in the game shop with special diamonds. You still still had to buy the diamonds, but they were times cheaper.
Example- An in game item costs $100. You connect your account to that-thing and the price gets changed to 500 diamonds. Now, you could already buy diamonds at a rate say $100 for 1200 or 1800 diamonds. So that's at least a 2x profit. I dont think it is possible anymore, but maybe those people have that thing since the beginning and so it still works...?