What Wattage do I need for my build?

Luke Winship

Reputable
Jul 20, 2014
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I'm sorry if I posted in the wrong place.
OK so finally started buying parts for my PC and may have got my priorities the wrong way.
I have already bought my,
Case: Aerocool X-predator Avenger edition
Graphics Card: Windforce 7950
CPU: AMD FX 6300
MOBO: MSI 970A-G43
RAM: HyperX FURY Series 4GB DDR3 1333MHz (will be upgrading to 8gb)

How much Wattage do I need? I thought I would only need a 500w but got told differently.
I have a £40 budget on PSU (not looking for brand names just something to do the job)
I will upgrade PSU in future but need something to hold on until then
(already have hard drive and optical drive)