While everyone is theoretically a potential buyer/user, it is not realistic. Purchases are made primarily by household with special age groups (Tweens, Teens, Senior Citizens), generational names (Baby Boomer, Gen X, etc), ethnic groups, life stages, and lifestyles. Geographic location, income, occupation, and education levels are often used, too. In some industries there is a category -- early adopters -- which is critical for launching a product.
Check Nielsen Segmentation & Market Solutions for all of the above categories. Take some time to play with this resource. You may be surprised at what you can find.
Check Mintel Academic Reports for the market of the product line, which also includes typical customers. Also check by generational, age and ethnic groups.
Check Passport for any market data or analysis of the market for the product line for any customer information and any demographic information.