Neb. Rev. Stat. § 49-1471: Neb. Rev. Stat. § 49-1471

A contribution or expenditure of more than fifty dollars shall not be made or accepted in cash. Contributions and expenditures of more than fifty dollars, other than an in-kind contribution or expenditure, shall be made by written instrument containing the names of the payor and the payee. Any person who knowingly violates this section shall be guilty of a Class III misdemeanor.