A basic 6 string guitar is recommended to start with, if that is what you want to know; the material used for the strings can differ from guitar to guitar but the 'basic' guitar strings have a pretty decent sound.
If you break one you can buy a new set of strings for around $ 5-10 (at least thats the price of basic electrical guitar strings, never bought new strings for my acoustic guitar. I don't think the price will differ that much).
Its easy to replace them and you can find how-to tutorials on the internet, or ask the guy at the store where you will buy the guitar to show it to you.
