45 Pa.C.S. § 304

All newspapers of general circulation, official newspapers and legal newspapers accepting and publishing official and legal advertising, are hereby required to fix and establish rates and charges for official, legal and all other kinds of advertising, offered or accepted for publication, and such publications shall furnish, on demand, to any person having use for the same, detailed schedules, stating the rates and charges which shall be deemed to be in force and effect until changed or altered, and, when changed or altered, such publication shall give the person authorized or required to publish advertising, before demanding or receiving compensation at any increased rate, notice that the rates and charges of such publication for advertising have been changed or abrogated, and that increased advertising rates and charges have been established or fixed.