Redmi note 3 was trending now a days . The best smart phone under 12000 is absolutely Redmi Note 3. This phone has two versions one is having 2Gb ram and 16GB internal and the second version has 3GB ram and 32 GB internal. Both versions are similar in processor and android versions. But the performance will be the little change. This is the best phone to buy under 12000. and one of my best phone using since last 8 months with good performance.