more than others because they don't know any better isn't ethical. Your general question, is it unethical to sell someone more of something than they need, I would say no, generally speaking that is ethical. Most of the things people buy they don't need. As a salesman, convincing someone to buy more product isn't unethical. Convincing them to pay more for the same amount of product or service level that you sell other customers at a lower price, unethical.