From PhpCOIN Documentation
Suppliers are those people and businesses that you purchase goods and services from, in order to run your business. For example, your ISP or hosting company is a supplier, as is your domain registrar.
phpCOIN can track information for suppliers, including the total amount presently owed to each supplier and one or more additional email contacts. Additionally, you can email a supplier or his/her additional email contacts, or even all suppliers.
When a supplier record is deleted by an administrator, all other records that rely upon the supplier record such as bills for that particular supplier are also automatically deleted.