LAW 101: Price Tag Rules:

1. It shall be unlawful to offer any consumer product for retail sale to the public without an appropriate price tag, label or marking publicly displayed to indicate the price of each article and said products shall not be sold at a price higher than that stated therein and without discrimination to all buyers.

2. The price tag must be written clearly, indicating the price of the consumer product including Value Added Tax (VAT) whenever the consumer product is VATABLE. Service charge, if any, shall not be included in the price tag.

3. All retailers who honor/accept credit/ATM/debit cards for payment shall not require the cardholders to pay a surcharge, extra charge, or additional charge over and above the price tag on the consumer goods and services.

Sources:
Sec. 81, R.A.7394 (“Consumer Act of the Philippines”). April 13, 1992.
Sec 2 & 5, DTI - Department Administrative Order No. 10, Series of 2006.