You are getting it confused.I didn't know that. I thought you had to use their packaging to get their rates...is the only limitation that the envelope you're using has to be the same dimensions as their packaging?
For example, the priority envelope is a certain size..if i get "custom" envelopes to use that has my logo on it, as long as they are the same exact size as the priority ones, USPS will accept it?
Unless i'm thinking about their priority mail FLAT RATE...you know the commercials where as long as you can fit it in the box, it's one flat rate... i'm slightly confused.
You can package anything you want and put a priority label and postage on it.