Taxi - There are a couple options for you to get from the airport to town. You can take one of the white taxis at the airport, which is the most convenient and most expensive way. Usually they charge around $60 US one way for up to 3 people. Cash only please!
Shuttle - If you want to save some money and have a little added security, you can book a shuttle van to pick you up here up to 7 people per van. Rates start at $150 US for a return trip and can include a stop at the larger grocery store, the Mega, on your way in.
Bus - The least expensive option is to walk over the overpass that crosses the highway at the airport. Wait at the bottom of the stairs for the public bus that goes to Sayulita. It is white, with a dark green bottom and will say Sayulita on the front window. This will cost $30 pesos, or about $2.50. The ride is about an hour and its last stop is the Sayulita bus stop, so no need to worry about where to get off the bus. Once there, there are taxis close to the bus stop that will take you to your destination in town starting at $50 Pesos.