My wife and I like to eat out on Saturdays and Sundays, especially our mid-day meal. That's mainly because our maid has those two days off. We try to find new places to eat for greater variety and over the years have found that for an occasional low cost meal the larger supermarkets are a good place to go.
The plato del día (plate of the day), which is available in most small eating places, consists of rice, black beans, a choice of meat, fish or chicken, mashed potatoes, salad, and a cold fresh fruit drink all for less than $4. We had a really tasty one at the little town of Tabarcia a couple of miles just off the highway to Puriscal. Once, while in a hurry and out of town, I also had a good plato del día for lunch for only $2.75 at a house in El Coyol, Alajuela, where two housewives converted part of one's living room into a small public eating place. Of course, I wouldn't recommend restricting yourself to the standard menu because of its lack of variety, but it does come in handy when you're low on funds and in a hurry. Vegetarians will find a large menu in the Vishnu chain in San José.
Another good place to eat in San José at low cost is the Hamburger Factory (several locations) which offers an excellent variety of red meat and chicken dishes cafeteria style. On occasions, if you go there after 2 p.m., two persons can buy for the price of one. A friend of mine, who visited me from Maryland, found the hamburgers there much better than the ones served by the known American franchises established in Costa Rica. Also worthy of consideration are the Mega Supers where you can have a good lunch at their food grills for less than $4, including a natural fruit drink and dessert.
For more expensive, though still reasonably priced places to eat there are La Cascada, Los Anonos and Tony Roma's (for ribs) in San Rafael de Escazú, and the Outback Steakhouse which lies along the highway to Guachipelin. Good eating places abound and sometimes you can be surprised at a good discovery. However, you could be dismayed at finding that a well-publicized place turned out to offer poor food, bad service and high prices - a complete disappointment.
For fish food, the La Princesa Marina (three locations) has very reasonable prices. Another excellent marine food eating place is El Banco del Marisco a few miles west of the town of Santa Barbara in Heredia Province. Such is its popularity that on Sundays you have to stand in line and wait for a table to be available. They usually have a full house from 12 noon to 3 p.m. They offer a good ceviche cocktail appetizer which is raw fresh fish seeped in lemon juice. The fried fish, whole and available in several sizes, as well as the octopus in garlic sauce, are excellent. At the Central Market in San José you can have a good ceviche for $2 with a free side-dish of tasty small slices of boiled green banana.