18 U.S.C. § 1466 : US Code - Section 1466: Engaging in the business of selling or transferring obscene matter

      (a) Whoever is engaged in the business of producing with intent
    to distribute or sell, or selling or transferring obscene matter,
    who knowingly receives or possesses with intent to distribute any
    obscene book, magazine, picture, paper, film, videotape, or
    phonograph or other audio recording, which has been shipped or
    transported in interstate or foreign commerce, shall be punished by
    imprisonment for not more than 5 years or by a fine under this
    title, or both.
      (b) As used in this section, the term "engaged in the business"
    means that the person who produces (!1) sells or transfers or
    offers to sell or transfer obscene matter devotes time, attention,
    or labor to such activities, as a regular course of trade or
    business, with the objective of earning a profit, although it is
    not necessary that the person make a profit or that the production,
    selling or transferring or offering to sell or transfer such
    material be the person's sole or principal business or source of
    income. The offering for sale of or to transfer, at one time, two
    or more copies of any obscene publication, or two or more of any
    obscene article, or a combined total of five or more such
    publications and articles, shall create a rebuttable presumption
    that the person so offering them is "engaged in the business" as
    defined in this subsection.