Mexico charges an airport departure tax of $18 or the peso equivalent for international and domestic flights. This tax is usually included in the price of your ticket, but check to be certain. Traveler's checks and credit cards aren't accepted at the airport as payment for this, but U.S. dollars are.
Puerto Vallarta and environs have a value-added tax of 15%, called IVA (impuesto al valor agregado). It's often waived for cash purchases, or it's incorporated into the price. When comparing hotel prices, be sure to find out whether yours includes or excludes IVA and any service charge. Additionally, Jalisco and Nayarit charge a 2% tax on accommodations, the funds from which are used for tourism promotion. Other taxes and charges apply for phone calls made from your hotel room.