Paypal's "Ship Now" has negotiated some great postage rates on shipping and now you can
benefit with this simple Paypal shipping link. There are no requirements for using Paypal shipping, so you can save, even if you did not sell an item through Paypal. Savings will vary, but on my last USPS flat rate priority letter mailing, I save approximately $1 over USPS prices. It is difficult to find on their site, so I am creating a link for you (and me) to use here.