Help with psu on i3 build

looking to build and i3 system and it will have a video card around a 4870 was wondering what would be the best psu for the job at the lowest price?

An i3 system will likely be at the very low end of the "how much power I need" spectrum. Unless you're going crazygonuts with hard drives (as in, having more than 5 or 6 of them), or adding another HD 4870 to the mix, nearly any quality unit (with the necessary two PCI-E power connectors, preferably) above about 400W will suffice, I would think.

To get a quality power supply, you'll rarely pay less than $50. But in that $50-$60 price range, there are great options to pick from.
Antec Earthwatts 500W (Delta-built)
Seasonic SS500-ET (Seasonic-built, of course)
Silverstone Strider 500W (FSP-built)
Corsair CX430 (CWT-built)
Even the Rosewill RG630-S12 gets passing marks from Gabe T.; a higher-powered unit, though you're probably sacrificing longevity due to less upscale (Teapo) capacitors. Not stellar, but I've been wanting to hear from some more sources how the RGxxx-S12 units perform. (ATNG-built)

The choice is yours.

A corsair 400w would do it if you don't add a second 4870 or OC the balls off it.
That's what i'd get.

The corsair 430 actually has 24w less 12v, donno why they did that, but it was a poor choice by them IMO.

I had a 4ghz e5200 and crossfired 700mhz 4830/4850 on my 400w. It dropped .03v under load.

I have an antec earthwatts 650 that will run 2-4870 and a highly oc'ed i7 and never had an issue. I would say corsair or antec for pure value and longevity. you can save a few dollars now and pay dearly for it later. get what you can afford from a reputable manufacturer.

400w is enough. just find any with 80 plus certified and long warranty. but better use at least 450w to make sure U always have spare power to supply system

thanks for the help

You betcha, we're always happy to help.