This issue is solved by mailing lists. In simple terms, mailing lists are a database of people having similar areas of interest or similar requirements. You can either generate these lists in-house or can hire one of the list brokers. If you do not have a team of specialized lead generation executives, it is advisable that you buy lists from a professional mailing list broker.
Mailing list brokers have access to several customer databases, as well as specialization in finding prospects for different lines of business. They can get you several credentials about the prospective clients such as telephone number, postal address, e-mail address, credit history, purchase history, etc. Based on your requirements you can choose the credentials you want your list to have.
Although availing the service of a mailing list brokers can be extremely beneficial for your company, you need to check a few things before you buy lists. Make sure that the list is recently updated as obsolete lists are almost useless for any marketing campaign. Furthermore, also ensure that the broker has prior experience in serving clients from your line of business.