In my opinion the mailing list if the most important part of a direct mail campaign. You can have a brilliant design, great copy and a well printed direct mail piece, but if it does not get into the hand of your target market, it is all wasted. The best list possible is the list that you keep yourself. If you are a non-profit organization make sure that you capture the names and addresses of volunteers, donors and others who may have come in contact with your charitable organization.  Those names are of people who know of your organization and the work that you are doing in the community by either volunteering or through donations.  If you want to mail to a larger number of people then use your list and buy some names to go with them.  Your mailer can do a duplicate check and combine the lists.  Over the years, I have had organizations want to mail to several thousand people that they acquire from a list company and then are disappointed with the results.  A good list takes careful planning and attention to capturing the names of people associated with your organization.

If your company is a for profit company and you want to purchase a list, then narrow your demographics to your particular market and then to the area that you want to mail.  Be careful to insure that you can handle the calls or business that the mail piece may generate.  If you intend to mail 25,000 then it might be a good idea to drop them 2000 at a time and see how much interest is generated and if you can handle the business that is brings.  If your not getting enough response with 2000 then drop 3000 on the next mailing until you hit the right number.  That is the good thing about mailing vs media, that it is trackable and can be targeted.