When you order a "Headache Free Out of State Kit" from Binary Biometrics we include a Prepaid USPS Priority return shipping envelope with postage. All prepaid shipping envelops with postage will expire six months after they are issued from Binary -- if you think your postage may no longer be valid please check with you local post office first, and if the postage is expired please call our office and will email new Prepaid postage for you to print and apply to the postage.