Is a stamp required for a priority flat rate envelope?

(2011-02-08 15:25:19) 1. Arizaki Says: It just hit me that a piece of mail I sent priority in a flat-rate envelope (payed the $4.95 for the envelope) did not have a stamp on it. Since I was with another person I tried to rush and completely spaced on the stamp. Did I forget something that wasn't required? Also, if it was required, will the piece of mail most likely be shipped and the recipient charged (it was to a personal address) or sent back to me? Thanks2. don r Says: If you did this at the post office they used the postage meter to put the stamp on the envelope. Tag: Is a stamp required for a priority flat rate envelope?