(1) Each agency shall:
(a) make available for public inspection all rules and all other written statements of policy or interpretations formulated, adopted, or used by the agency in the discharge of its functions;
(b) upon request of any person, provide a copy of any rule.
(2) Unless otherwise provided by statute, an agency may require the payment of the cost of providing such copies.
(3) No agency rule is valid or effective against any person or party whose rights have been substantially prejudiced by an agency's failure to comply with the public inspection requirement herein.