Your question is way too vague for a decent answer. There are so many factors to consider, such as where you are located, how big of a place you want to have, what kind of clientele do you want, etc.
I just wrote a hub about steps to starting and/or purchasing your own business that might help you:
If you shoot me a message with more info about what you are looking to do, I would be happy to write a hub in more detail about what you would need to do to open up a restaurant as I have several business plans that I have done in the past in that similar realm.
All the best!