If Rogers and Apple sell the iPhone 3GS in Canada at a no-contract price, this doesn't mean the iPhone will be unlocked. The iPhone is sold in Canada as carrier locked with Rogers only.
Once again - the iPhone is sold in Canada as carrier locked with Rogers only. Carrier locked means the iPhone sold in Canada can be used with a Rogers activated SIM card.
I believe the iPhone is sold by Apple in India and if so, you should purchase an iPhone in India where you will have support and where Apple will honor the warranty for the iPhone if needed.