For a Pluma [1] overnight, consider new Hotel Posada Isabel (Calle Guerrero, tel. 958/525-8113, joesue24-7 [at] yahoo [dot] com, $20 s, $25 d). The Posada Isabel, located just southwest of the church, offers six clean rooms, some with view balconies, and all with two double beds and private shiny-tile hot-water bathrooms, with TV and parking.
Also, friendly family-owned Restaurant Luria (Av. Hidalgo 16, tel. 958/525-8022, $10 s, $15 d) rents three rooms—two with two double beds, the other with one double bed—above the restaurant. Rooms are spartan but clean, with cross ventilation and private tiled bathrooms, with fans and hot water.
Furthermore, Restaurant Luria (6 a.m.– 9 p.m. daily) offers hearty Mexican country specialties. Besides Mexican breakfasts, food offerings often include chicken smothered in mole negro, mole coloradito (spicy chile usually over pork or chicken), or estofado (meat and vegetable stew), all for about $4.
Alternatively, try plaza-front Restaurant La Flor del Café (Calle Guerrero 1, 6 a.m.–9 p.m. daily, $3–6), which offers traditional Mexican plates, such as guisado de res (beef stew) and chilaquiles (spicy baked tortillas and cheese).
Links:
[1] http://www.moon.com/destinations/oaxaca/pacific-resorts/bahias-de-huatulco/excursions/pluma-hidalgo