Usps Large Flat Rate Box Size Cost. From $58.06 for commercial plus. Your own box by weight/zone:
Your own box by weight/zone: Priority mail flat rate shipping supplies boxes. 12″ x 12″ x 5.
USPS Flat Rate Shipping Option
Usps Large Flat Rate Box Size Cost Usps mailing box (flat rate):medium flat rate boxes. Priority mail flat rate shipping supplies boxes. Usps mailing box (flat rate):