Hey I am doing a project for school, and in the project I am "running" a shop kinda like cafepress.com. I have to figure out how much bandwidth we would need to keep this "company" up and running. Thank you. "If confusion is the first step to knowledge, I must be a genius." ...Larry Leissner...

You need to run some stress tests. You can hire a company that does this kind of thing. They will basically simulate multiple users using your site and determine at what point the system will become unstable or the process too slow for users. This can be expensive though. Alternatively you can get a sample of people to use the site over a set time-period. Then evaluate the bandwidth used during that time period to determine how much you would need based upon the projected usage. There are no magic numbers here. Unless you know how many people will be using your site you can't say what is "enough" bandwidth. At some point bandwidth won't be as much of an issue as the servers (web, database, etc). Then you have to determine how many servers you need to meet the demand. Michael J