It sounds to me, although you don't say this, that you want to shoot images of people on the streets in the likeness of what NatGeo would do, right? First off, you need to practice a lot to get images like that; the photographers they hire are professionals who have wonderful ability and most likely years of education and/or practice. At first in photography, it's not about the equipment, it's about getting the shot right and any camera can do that if the photographer uses it correctly and artistically. Practicing photographing any people will help you attain this goal. There are hundreds of people shots to be gotten anywhere you go, it's about having an eye for the shot and this, too, can be attained if it does not come naturally. In general, the viewing public likes shots of children (doing something or looking cute), babies, old people of either sex, people interacting, people in less than optimal situations (i.e., homeless or street people), and this is just for a start. Street scenes are often viewed in black and white as the starkness of BW adds to the image. I think you need to work on getting "an eye for the shot" and not worry about having expensive equipment. If you have a decent iPhone or other type of smart phone you can even start with that. Having expensive equipment does not automatically make any of us better photographers. Read up on people photographers and look at their images to learn more. Check out Werner Bischoff (I just went to an exhibition of his work) as well as the premier people photographer, Henry Cartier-Bresson who founded Magnum Photos in 1947.