Even if I utilize a flat rate Priority envelope? Do I just obtain flat rate postage, adhere it within a Priority twelve.5x9.five envelope, and drop it in a very blue box? Pick FROM 25+ U.S ADDRESSES We are Qualified partners of USPS and we will forward mail to any https://shipvista.com/blog/are-you-an-amazon-seller-ship-your-orders-with-shipvista-com