How much supply would i need?

[Game_sickness]

I am planning to buy a pc with amd radeon rx 470 and intel core i3 7100 how much power supply will i need and also suggest some.

 

[Zerk2012]

450 Watts would run that easy and allow for a bit of upgrades for the price of a quality 450 watt power supply you can spend a few more dollars and get a 550 Watt that would be good for about any future upgrades you could make.
Sorry I can't recommend a lower priced cheap PSU.
http://pcpartpicker.com/products/compare/xVkD4D,DPCwrH/