Whenever you go to buy a mobile phone , just dont think about expensive or cheap , just go for something which is latest , when ever you want a new device just dont go for cheap deals which have old feature , go for normal deals , first of all make your mind that what do you need the mobile for , calling, camera, games, multi tasking, performance, watching movies etc ,
dont go for a 3G device always buy a 4G device
for calling
just go for a basic mobile phone which have normal 1gb ram 8 gb rom 5-8mp camera
for camera
you need to buy phone which atleast have 8-13 mp of camera now a days mobiles come which have dual camera
for games
you need a device which have a good processor and high ram , without good processor and high ram your device will heat up , you need both of things to balance your device good processora are like snapdragon
for performance and multi tasking
like you need to switch between apps , like you have to take a picture share it on whatsapp and then instantly share it on facebook then on instagram you need a high ram phone which will not lead to hang problem . high ram phone I would suggest redmi note 4
for entertainment
you have to find a device which have IPS HD display
and larger screen if suits you
dont go for small screen devices if you need to watch movies and stuff it will just hurt your eyes
at the end keep this in mind mehnga roe ek baar , sasta roe bar bar