I want it to look like natural light.
what kind of bulbs do I need?
where do i buy them?
"Natural light" can have many different looks. cloudy, sunny, midday or late afternoon. So there is no one thing that is "natural light". And you didn't say if you are shooting photo of video. However, If you are looking for a soft daylight source that can be used for photo or video I recommend a white umbrella of at least 30" in diameter with a daylight (5500K) balanced CFL bulb of 65 or 85 watts. All cab be found on the Adorama website. You will also need a light stand along with the socket pictured here.