Jamiltepec [1], capital of the Jamiltepec governmental district, has a number of basic hotels, restaurants, and services (but not yet a bank) near the town plaza. For an overnight, take a look at the Hotel Díaz (Hidalgo 4, tel.958/582-9103, fax 958/582-8050, $10 s, $14 d) at the northeast plaza corner. It offers a dozen clean, basic rooms around an airy upstairs patio, with fan and private bath (but room-temperature water only). (If the Hotel Díaz is full, take a look at the Hotel Maris (tel. 954/582-8042, $17 d) or Hotel Pérez (tel. 954/582-8249, $20 d), both on Calle Josefa O. Domínguez nearby.
Additionally, out on the highway, at the west edge of town, consider Jamiltepec [1]’s newish, semi-deluxe Hotel Mirador (tel. 954/559-2448, $18 s or d in one bed, $25 d with two beds with fan, $20 s or d in one bed, $30 d in two beds with a/c), perched on a view hillside, next to Highway 200. Fine for an overnight, the Mirador offers about 15 comfortable (if a bit dark) rooms. All with hot-water shower-baths, parking and an acceptable restaurant.
Links:
[1] http://www.moon.com/destinations/oaxaca/pacific-resorts/-mixtec-coast/santiago-jamiltepec