<< Check to make sure they don't charge you for it. It seems like they don't keep their employees informed of this, and even if they know they don't understand it completely. I had a postal clerk deny me purchasing a priority mail postage cause she thought that the shipping was free, not just the delivery confirmation. I was worried that my package didn't ship but it did. Print out the page too just in case. >>
Yeah, printed out a label for my idiot parents to send something to my sister at DUKE, but they bent when the postal clerk said:
"Nope, its only free when you purchase postage online too" I was like, WTF, you can't even buy postage on USPS.gov!!!