Direct mail and catalogues, as with periodicals, benefit from discounted rates in many countries.
The qualification requirements do however vary country by country and the discounts are often not as generous as for periodicals. The principal restriction is volume. That is, you will require more items per mailing or group of mailings per country to access the most beneficial postal tariffs.
Examples of services include Mailsort (UK), Infopost (Germany), Bulk (USA) and Massendenseng (Austria).