This post details how to get from San Salvador to La Libertad in El Salvador on a chicken bus.
Bus 102 to La Libertad makes a stop here: SE corner of Parque Cuscatlán on 25 Avenida Sur in San Salvador.
Journey time was 65 minutes, the fare just 59 cents. Traffic can be bad getting out of town.
The best place to get off the bus is near the dock. It is also the most convenient place to get the chicken bus going back to San Salvador