Eight-to-sixteen-passenger vans, although less comfortable than first-class buses, provide faster service (at about the same price). They are becoming increasingly popular for medium-distance connections, especially for Pacific coast destinations of Pochutla [1]–Puerto Ángel [2].
At least two operators provide Oaxaca–Pochutla connections, from stations about one block east, three blocks south of the zócalo’s southeast corner. The first option is Eclipse 70, which departs about every half hour during the day from Armenta y López 540 (tel. 951/516-1068, Pochutla $12). Alternatively, around the second left downhill corner, you can ride Atlantida (Noria 101, tel. 951/514-7077) every two hours for the same price.
Links:
[1] http://www.moon.com/destinations/oaxaca/pacific-resorts/puerto-angel/upland-excursions/san-pedro-pochutla
[2] http://www.moon.com/destinations/oaxaca/pacific-resorts/puerto-angel