According to me these are the best smartphones to buy, which are priced around Rs.12,000 :
Coolpad Note 3
5.5 inches, Octa Core, 1.3 GHz, 3 GB RAM, 13 MP Primary LED Flash and 5 MP Front, 3000 mAh (Non removable) battery and Inbuilt 16 GB + 64 GB Expandable Memory
Xiaomi Mi4i
5.0 inches, Quad Core, 1.7 GHz, 2 GB RAM, 13 MP Primary Dual-color LED Flash and 5 MP Front, 3120 mAh (Non removable) Battery and Inbuilt 16 GB (Non Expandable) Memory
Asus Zenfone 2 Laser ZE550KL
5.5 inches Display, Quad Core, 1.2 GHz Processor, 2 GB RAM, 13 MP Primary Dual-color LED Flash and 5 MP Front Camera, 3000 mAh Battery (Non removable) and Inbuilt 16 GB + 128 GB Expandable Memory.
Yu Yureka Plus
5.5 inches Display, Octa Core, 1.5 GHz Processor, 2 GB RAM, 13 MP Primary LED Flash and 5 MP Front Camera, 2500 mAh Battery and Inbuilt 16 GB + 32 GB Expandable Memory.
Lenovo K3 Note
5.5 inches Display, Octa Core, 1.7 GHz Processor, 2 GB RAM, 13 MP Primary Dual LED Flash and 5 MP Front Camera, 2900 mAh Battery and Inbuilt 16 GB + 32 GB Expandable Memory.
Check the complete list of Smartphones priced under 12000