The best way to purchase your direct mail campaign is to use a direct mail company that does everything in-house (like PostcardMania). This keeps advertising costs and stress down, because you can get design, printing, and mailing services handled under the same roof. These direct mail vendors coordinate with USPS to ensure you pay the lower “bulk mail’ postage rates, plus you get a campaign manager who can provide marketing tips and guide you through any relevant direct mail templates and options (and show successful examples).