You should go read some of the articles on our site
xxhttp://www.hosting-review.com This website should help you…
Your questions are pretty broad sweeping and in order to properly answer the questions you would have to provide the requirements for your website. What are you trying to do?
I would start out with a shared/virtual hosting plan until you are familiar with the process…you will get plenty of space and bandwidth for 99.9% of most websites. Once you exceed this, you can always move your domain to a dedicated server plan.
Hope this helps…