I am new too. It all depends on what you are
going to use it for. Give more detsils about your
objectives to get the lens. I am sure many veterans
will be glad to share their knowlegde with you.
I agree with chiangkxv. Shooting more will allow you to explore
the various aspects of photography. When you have done enough
you will be able to accurately focus on your areas of interest.
This will direct you to the type of lens you will need.
Unless you have deep pockets then its a different story.
You can visually inspect it. Remove the lens
from the camere and both the caps at its ends.
Look through it at a light source. If you can see spots
it could be just dust or fungus. You can see
cleary if the fungus is in an advance stage.
It looks similat to the fungus that grow
I assume u have the 18-55mm that comes with the d3000? with a budget of 200, I guess the logical choice would be the 55-200mm or 50mm f1.8. 55-200 gives u more zoom capability which continues quite nicely with your 18-55mm. 50mm f1.8 is a much faster lens which will allow u to take pretty clear pics under lower light conditions. But cant auto-focus in your d3000.