If you HAND the envelope to the postal clerk to affix postage, that's the correct rate that will be charged for non-machineable mailings. If you pre-affix your postage at the current rate and drop it into the collection chute, or put it in your curbside mailbox for pickup, chances are it will fly. I've not had one returned yet. However, you take the chance that your chip may arrive at its destination broken, so I would not advise your front and back cardboard method for mailing out valuable chips.