Mexican brothels (called casa de citas, or "house of dates") exist in Puerto Vallarta, In a tiny town like PV with it's huge population of prostitutes working in the strip clubs and as escorts , there aren't enough Mexicans to support brothels. Fortunately, the cruise ship crews have needs. Ask a taxi driver to take you to Las Alazanas or Las Antorches. Another strategy is to go to the strip clubs first, and finish up with a cheap piece of chiquita at the casa de cita. Talk to your tour operator.
Antorchas is just across from the ferry terminal. They only charge $500 for some pretty fine looking girls. Sometimes they have 3 girls. Sometimes they have 30. A lot depends on whether the cruise ships are in. That's where the Mexican stewards go. Don't freak when you choose a girl and she takes you out back. It's a 100 yards across a built up, narrow boardwalk across a swampy lot behind the Antorahas bar. After dark, it's downright creepy. However, nothing bad ever happens and she's leading you to a small house with several basic, clean bedrooms. This may be the best brothel experience in Mexico.
You'll pay around $50 USD. (They won't take US Dollars or your American Express card. Convert your money to pesos before you go have a good time.)