N.Y. GBS. LAW § 519 : NY Code - Section 519: Disclosure by commercial establishments honoring credit cards

1. Any person who honors credit cards that may be used  to  purchase  or
  lease property on the credit of the issuer or of the holder and requires
  a minimum purchase before accepting credit cards or refuses to allow the
  use  of such card on discounted or sale items must post such limitations
  or conditions conspicuously and in all advertisements that mention  that
  credit  cards  are  accepted.  The disclosure provisions with respect to
  these requirements shall be satisfied if the retail  installment  credit
  agreement  discloses the fact that the use of the credit card requires a
  minimum purchase or shall not be used to purchase sale items, or if  the
  issuer of the credit card notifies the holder in writing that the use of
  the  card requires a minimum purchase or that the card shall not be used
  to purchase sale items. This section shall not apply to minimum purchase
  requirements or other restrictions which are  applicable  regardless  of
  the method of payment.
    2.  Any  person  violating  the  provisions  of  this section shall be
  subject to a civil fine of not more than  one  hundred  dollars  on  the
  first  violation  and  not  more  than  two hundred fifty dollars on the
  second and all subsequent violations.
    3. This section does not annul, alter, affect  or  exempt  any  person
  subject  to the provisions of this section from complying with the laws,
  ordinances, rules or regulations of any locality relating to  disclosure
  of  limitations  and  conditions of credit card purchases, except to the
  extent that those local  laws,  ordinances,  rules  or  regulations  are
  inconsistent  with  any  provision  of this section and then only to the
  extent of the inconsistency.  However, any local law, ordinance, rule or
  regulation shall not be considered inconsistent with  any  provision  of
  this  section  if  such  local  law, ordinance, rule or regulation gives
  greater protection to the consumer.