That is a loaded question. If you want to pay for a mailing list, you can certainly do so. However, it's really best to build your own list based on your own personal interactions. In other words, start with the people you know and then work your way out from there. If you purchase a mailing list, you'll likely be doing so for business. The problem is that there's no guarantee that a purchased list will provide you with the business boom you're hoping for, and people can charge any amount of money they want to charge. So it's really best to keep things authentic and reach out to the people who are most likely to give you their business first.