Do i really need 4 cores

I am new to pc's and i was woundering do i really need 4 cores for light gaming and web surfing?

for light gaming no but if you can get quad core go for it 

Yes. It noticeably improves performance and multitasking.

You will need quad cores in gaming anyway, I see quad cores becoming a requirement within two years. Multitasking needs the quad core to be decent.

There's a quad-core CPU out there for every budget. ;) 

Short answer:

Tree.

for "light gaming and web surfing"

no

Nope but the A10-5800k is really cheap as well as the 6 core FX-6300 which these will be just fine for gaming. I know future titles will start using more cores but these are perfect at the moment for any need you might have. The A10 has a great integrated GPU which is really nice. I have one myself cross fired with a graphics card and I never have any trouble running the games I play. 

^this, if you already got a GPU then get a 6300, if not grab a APU quad core, they have better iGPU anyway