I found some shipping info that some of you might be interested in.
On the USPS site
https://sss-web.usps.com/cns/landing.do you can set up a business shipping account with a credit card and pay less than the P.O. counter rates. It allows you to print a label with postage on it. A 1 pound Priority package is $4.75 instead of $4.80 and larger packages are up to 11% discount. A nickel isn't much but if you ship very much it could add up. It could also save driving to the Post Office.