When you purchase a web hosting server with the intent to start your very own hosting company and to resell packages to various other people, you may as well wish to sell domains, to give your customers the chance to buy everything they need for their new site from just a single place. To become a licensed registrar involves thousands of dollars along with a lot of documentation, so the most convenient solution would be to register for a domain reseller account with an existing registrar company. Your reseller site will be connected to that account through the registrar's API. To use such an account has many different pros - your customers will be able to get and to manage new domains with ease; the price for a brand new registration will be lower compared to what you'd need to spend as an end customer; also you're able to start reselling instantly. The registrar companies which provide domain reseller accounts almost always need some money as a deposit.