How much bandwidth do I need?
To determine how much bandwidth you need, you must first:
estimate how big each page on your site is, and how many people are going to view it.
To do this, add up the size of every image on the page and the size of the page's HTML files. Then multiply this figure by the number of views you expect for that page per month.
For example, if you had three 10kb images on your page and a 2kb HTML file, you would have 32kb of data on that page. Multiply that by your expected page views (let's say 1000 per month), and you get 32 mb of data to be transferred that month for that page.