N.H. Rev. Stat. Ann. § 31:8

For the encouragement of equitable taxation and the education of public officials in tax problems and other matters pertaining to the proper and efficient discharge of the duties of their respective offices, each town and city shall pay annually to the New Hampshire Association of Assessing Officials, the New Hampshire City and Town Clerks' Association and the New Hampshire Tax Collectors' Association, such amounts as shall be due for annual membership for its officials therein, providing that the amount paid for any one annual membership hereunder shall not exceed $20. Members of these several organizations in addition to the annual membership fee, shall be entitled to receive their actual expenses incurred in attending the annual convention of their respective associations, the same to be audited by the selectmen of towns and the finance committee of cities and paid out of city and town funds.