Abstract: An apparatus ideally suited for the small mailing service is disclosed. The apparatus can take pro-printed, un-addressed mail pieces of non-identical size delivered to the mailing service from different merchants and combine the mail pieces to create mailing bundles at the lowest postal rate and group the bundles to create a single mailing. In the apparatus a computer serves to take the merchant mailing lists, merge and sort the entries thereon into lowest postal rate groupings, and use this merged data base to enable a sequence controller and associated machinery to physically commingle and address the non-identical mail pieces into the single mailing bundle. Provision is also made for generating required postal service documentation and invoices from the mailing service to the merchants.