This is a bit of an open ended question, but to help you understand how BitBuffet works think of it as an intermediary between the customer, you and PayPal. Your customers cannot simply browse BitBuffet.com to find your products, you must have some sort of web presence so you can display a button that redirects them to us and then to PayPal.
Most of our customers are trying to sell a digital product from their existing website or web presence. For example, say a band wants to sell their album and has a popular MySpace page. They can upload their album to BitBuffet in zip format and place the button code on their MySpace profile.