Purmamarca is located north of Salta and Jujuy close to the intersection of RN9 and RN52. This makes it a good base for exploring the north. Tour operators in Salta offers two day combo tours to the north and will drop you off in Purmamarca on the way back the first day and pick you up there the second day. That saves you several hours of driving both days.
Buses from Humahuaca (via Tilcara) and Jujuy.
You can easily walk around Purmamarca.
The old pueblo and church, with worn cobblestone paths, and feel as though you had gone back 200 years or more.
A small market loaded with items of all kinds, including Bolivian hand-woven blankets with nice, authentic designs. Wise, knowledgeable and friendly shop owners, though they may be difficult to find at siesta time.
There are many good restaurants.
If you go to Purmamarca as part of a tour, the tour operators are good at arranging lodging for you.