N.J. Stat. Ann. § 18A:6-8

No person officially connected with, or employed in, the public school system of this state or in any state educational institution shall be an agent for, or be in any way pecuniarily or beneficially interested in, or receive any compensation or reward of any kind for, the sale of any textbooks, school apparatus or supplies of any kind, for use in the school district or in the state educational institution with which he is connected or by which he is employed or within the state or part thereof over which his jurisdiction extends, upon penalty of removal from office or of revocation of his certificate to teach or to administer, direct or supervise the teaching, instruction or educational guidance of pupils in the public schools, but the prohibition of this section shall not prevent any person from receiving royalties upon the sale of any textbook of which he is the author.