Gigabyte is the cheapest of the lot.
It will be around Rs2200.
Actually 3-4 months ago I planned to upgrade my GPU and PSU.
I ended u buying a 9800GT(Zotac,cost around 5.8k) And the corsair CX400 for 3k.
Well the corsair seems expensive but it is worth every penny.
Well here is the link for gigabyte Superb price...http://www.lynx-india.com/index.php?productID=6527
You can also ask on desi forums about this PSU...