N.H. Rev. Stat. Ann. § 365:13

When any such summons shall be endorsed by the secretary, or assistant secretary, or by a commissioner, as follows, "Legal fees of witnesses guaranteed by the State," advance payment of fees shall not be required, but any witness served with such summons shall appear as directed therein as a witness for the state, and his legal fees therefor shall be paid out of any appropriation for the use of the commission available for the purpose.