You can't get it for <20K. But it would really be worth shelling out that extra bit of money to go for the Nexus 4 (on eBay it's 23k-25k). After all, once you buy a phone, you're going to keep it for a long time. Better spend that extra bit of money and get a really good phone than getting an average one for a lesser price.
On Flipkart, with the Standard Chartered 15% cashback offer, you can get it for ~20.6k. However, the 15% cashback offer is only till the 19th of this month; afterwards it's only 10%.