Recommended restaurants are listed according to location and cuisine type. Many of the best restaurants can be found in the suburb of Escazú [1], within a 15-minute drive of San José [2].
Sodas—cheap snack bars serving typical Costa Rican fare—are a dime a dozen. They serve “working-class” fare, such as tripe soup, and chicken with rice-and-bean dishes. You can usually fill up for $2–4.
Within the warren of the Mercado Central [3] (Calles 6/8, Avenidas Central/1, Mon.–Sat.) and adjoining Mercado Borbón (Calle 8, Avenidas 3/5) are stands selling poultry, flowers, meat, fish, medicinal herbs, fresh produce, and coffee.
The Mercado Paso de la Vaca (Avenida 7, Calle 6) is a clean produce market selling everything from fresh herbs to meats; take a taxi and be careful walking around this area.
Links:
[1] http://www.moon.com/destinations/costa-rica/central-highlands/escazu-and-vicinity/escazu
[2] http://www.moon.com/destinations/costa-rica/san-jose
[3] http://www.moon.com/destinations/costa-rica/san-jose/sights/west-central-downtown/mercado-central