USPS First-Class Mail®, First Class Postage

Cost of First-Class Postage Stamp - U.S. Postal Facts

First-Class Mail & Postage

USPS First Class® vs. USPS Priority Mail® vs. USPS Retail Ground®

Mail & Shipping Services

First Class Mail: What is it and How to Send It - PostGrid

Indicia/Permit Imprint for Postage

USPS® postage rate change overview

First Class Postage Explained - Postalytics

Stamps, First-Class Mail