I'm confused about changing lenses with cameras? - 1

This is the camera i'm getting: http://www.amazon.com/...003ZYF3LO/

So if i wanted, i could buy, lets say this lens: http://www.amazon.com/...001S2PPT0/

And it would fit fine?

Could I just buy any nikon lens?

Yeah, that's a G lens.It'll work fine. Check:

http://www.kenrockwell.com/...y-lens.htm. For lenses compatible with the D3100.

Yes, that lens will work fine. You can buy any nikon AF lens and it will fit. HOWEVER if you want it to auto focus on your camera it will have to be an AF-s lens as the d3100 does not have an auto focus motor in the body.