Hi, I love the sound of the violin.  How do you tune a violin?
The violin is a great instrument! It has four strings and is tuned in perfect fifths.
That's neat. What are violin strings usually made out of?
There are many different types of strings that can actually change the loudness and tonal quality of the violin. The tension can also change things as well.
What kind of wood is typically used to make a violin?
I am actually not sure, but the body of the violin is completely hollow. 
How much does it usually cost to have strings put on a violin?
Prices would vary depending on the company, but you could also pay to have other parts such as the tuning pengs, tailgut, endpin, or chinrest repaired as well. 
Sounds like it might be expensive.  What does one need to do to maintain a violin?
There are also some other types of violins as well that aren't very common.