Your question is asked here about 1000 times each year. Some suggestions:
1) Read the newbie links.
2) Read the newbie links.
3) Read the newbie links.
4) Do a search here for bass buying threads and read the advice.
5) If you are considering buying a new instrument, then in order to get a decent entry-level bass (e.g., a Shen) delivered with a proper and quality setup, you'll need to spend a minimum of around $1500. There's no way around it unless you're willing to buy a disposable instrument that you'll work on yourself rather continuously. The setup is HUGELY important.
6) Buy from a real bass shop. Avoid online mass merchants and guitar shops.
7) Get a teacher. The DB is related to the BG but is a very different instrument. A teacher will help you to avoid injury and set you on the right path.
8) Fill out your profile so we know a bit more about you.
9) Read the newbie links.
