For example, if you had three 10k images on your page and a 2k HTML file, you would have 32k of data on that page. Multiply that by your expected page views (let's say 100,000 per month), and you get 3.2G of data to be transferred that month for that page.

Now recalculate this number for each page, and you will know approximately how much bandwidth your entire site requires.

How can I save bandwidth?

There are two key ways to optimize your bandwidth usage:

1. Keep your pages as small as possible.
This means tight HTML programming to reduce file size, and compacting your pictures and graphics to reduce image size.

2. Secure your website.
This is too detailed for one paragraph, but a great article is located here when your ready.

Policing bandwidth

The most basic method of preventing theft of your bandwidth is policing. Analyze search engines, logs, and other sites to find out who’s using your images (and your bandwidth) without permission.

Once you've identified the offenders, you can contact them and order them to stop linking to your site (and if they try to feed you a story about everything on the Internet being in the "public domain," don't buy it). Unfortunately, policing sites yourself is a time-consuming task.