You pay no fee for a New Hampshire peddler's license if you have a service-connected disability. The unremarried surviving spouse of an eligible disabled veteran is exempt from the fee too.
Apply for the peddler's license and ask for the veterans fee exemption, showing your VA disability documentation. Confirm with the licensing office which forms it wants, because the source does not name one.
Your VA rating letter showing a service-connected disability, your DD214, and, for a surviving spouse, a marriage certificate and the veteran's death certificate.