Apple unveiled iPhone 5S on September 10, 2013 at Apples Cupertino headquarters.
Reports are saying that Apple will unveil iPhone SE on March 21. iPhone 4S was recently discontinued by Apple in India thus making iPhone 5S as the low cost iPhone.
Also, iPhone 4S was available at similar price as iPhone 5S will be, before it was discontinued.

This might be new sales strategy for the Apple.
So you will have to longer wait to shop it, when it is readily available.

