Earlier this month, Microsoft launched a 'Lumia 535 Smart Buyback Offer' in India in which you could exchange your old phone in a working condition, and buy a new Lumia 535 for ₹5,999 (US$ 90), inclusive of all taxes.
This offer is available on purchase of Lumia 535 at all the authorized re-sellers of Lumia devices across India till stock lasts.
Additionally if you've bought a Lumia 540, Lumia 640, Lumia 640 XL, Lumia 730, or a Lumia 430 in the offer period (Starting August 7, 2015), you can get a cash back of up to ₹3,600 in your MobiKwik wallet. The cashback offer can be redeemed over a period of one year, ₹300 per month, by using the code 'LUMIA300' to avail the offer.
If you're looking for a budget Windows Phone device, Lumia 535 is a pretty good option on the table, although ₹5,999 isn't really a steal considering there are newer models available in the sub-10K price without buyback. Of course, if you are looking to buy a nice, little Windows Phone device, you'd want to make use of the offer and save some bucks. You can find the list of qualifying handsets here.
And if you're buying any other budget Lumia phone, make sure you use the MobiKwik benefit. The cash back that you can use for your mobile payments as well as across many online and offline merchants, will make buying a Windows Phone device a pretty sweet deal.