Looking for a new phone for mom with budget of 12k.
Requirements
Long lasting battery (Especially with Bluetooth headset usage).
Screen Size : 4 ~ 5"
Dual Sim: Preferred.
Mico USB charging : Preferred
Most other features are low priority.
Lenovo P770? I guess it ticks all the boxes though 1.5k more than your specified budgt
My vote will go to Nokia Lumia 520. It has got a pretty interface. You can get a nice chic colour. I’m assuming it’ll last her a day (bluetooth) if she won’t use it for watching videos and listening to music. You can ask this on the Nokia Lumia 520 thread and someone will surely get back. I got a NL720 and man the battery is amazing. Last me 40 hours on an average.
I don’t know what it is, but middle aged women seem to love Lumia 620.
I too had gotten a WP phone with the plan of giving to my mom. However she was adamant on a dual sim. Which is a sorely lacking feature in WP.
Got a Karbonn.
Sent from my PantechP9070 using TechEnclave Forum mobile app
What phone you got in Karbon? and how is it?
Lumia 520. 
@vivek.krishnan which Karbon phone u got???
Dunno, some cheap Android phone. My bro is using it now for the time being.
Check the XOLO Q800 too…
Lumia 520 is the best in that price range for your mom. Android phones in that price range usually hang. WP 8 is superb.
It has all the features that your mom would need.
It doesn’t have front cam and led flash though. But i think your mom wont require those features.
Agree with the post above… WP8 is amazingly simple and creative unlike Android, which I consider is for pro users.. Specs are amazing, fluidity is uncomparable is this price range
Btw… I really appreciate people taking stuff for your mom
Lenovo P770 dude. It ticks all your requirements and also has a 3500mAh battery.
Is smartphone even a necessity?
What about Asha series?
Edit: Just realized the OP was very old. Perhaps the decision has already been made.