Can I use AF Nikkor 50mm f/1.4D with Nikon D3100?

I have a Nikon D3100 and I'm new to photography. I would like buy a 50mm f/1.4 lens. Can I use AF Nikkor 50mm f/1.4D with my camera or shall I buy AF-S Nikkor 50mm f/1.4G which is more expensive lens?

You can use the Nikkor AF 50mm f1.4 prime lens on your D3100 but it won't auto focus. If you want auto focus then you'll have to pay more and buy the Nikkor AF-S 50mm f1.4 prime lens. Only Nikkor AF-S lenses will auto focus on your camera.

You can, yes, but the more expensive version (AF-S) will autofocus, whereas with the cheaper one you will need to manually focus it.

Pre-digital Nikon-mount lenses can be mounted and used on digital Nikons, however, you will only be able to use the camera in full manual mode. Which is why you can get many good-quality older lenses for under $50, compared to $200-500 for an equivalent CPU lens. Given that zoom lenses have gotten to the point where there's little noticeable difference in quality between primes and zooms, you'll probably be wanting a more versatile lens pretty soon, anyway. If you really want to learn photography, and not just get good no-brain pictures, a manual camera is a better teacher than a photography manual.