By public transport the easiest way to get to Purmamarca is from San Salvador de Jujuy (65 km away) Buses cost 7 pesos and take 1¼ hours, leaving every one to two hours;
Purmamarca is also a stop on many/most of the major tourist buses. They will stop there usually for an hour on the way back from the Cuesta de Lipan or Quebrada de Humahuaca. If you are staying in town for a night or two you can arrange with the tour company what day you want the bus to pick you up.
Tilcara, which is the nearest major town (25 km away)- buses cost 3 pesos and take about 30 minutes.
Bus to Humahuaca cost 8 pesos and takes 1¼ hours.
Purmamarca has no gas station; the closest can be found 25km north, at Tilcara, or south, at Volcán. Westward, the next gas station is in Susques, 130km of steep climb away.
Regular buses run between Jujuy and Bolivian border, along Ruta 9, the main road through the Quebrada de Humahuaca. Many of these stop at Purmamarca, which is 3km west of the main road, and 65 km north of Jujuy.
We based ourselves in Tilcara for 4 days and took the scenic route down to Purmamarca, travelling by bicycle. It was downhill for most of the 25 km between the two, and we passed some beautiful landscapes, including the Pukara near Tilcara and the so called Painter's Palette near Maimara.
Returning to Tilcara was a tough 25km uphill, but with such amazing views to compensate for the tough cycling, we barely noticed the hardship!