There were two different sized envelopes used for the return ballot.
If the return voter envelope has $.50 postage on upper right corner on the front of the envelope and $.50 postage on the upper left corner of the back of the envelope then no additional postage is needed.
If you only have $.50 postage on your return envelope you should check with the Post Master to make sure it is sufficient postage.
According to the Niobrara Post Master – Ballots are handled differently and they know they are ballots because of the information printed on the back of the envelope. So if you have already mailed your ballot back, the post office should realize that these are ballots – and they will come back to the Election Board Mailbox and the Election Board will pay the postage due. The fact there is no return address is not an issue. If you have any questions, please contact the Election Board via e-mail firstname.lastname@example.org.