The El Gruillense chain in and around Redwood City is okay for cheap eats too. There are several locations.
Also, the tacqueria counter in the Chavez Market on El Camino in RWC is good. The store is worth shopping in too. They have really good prices and lots of Mexican ingredients plus a good butcher that has some prepared items (salsas, al pastor, guacamole)
Rose Market in Mountain View. The best cheap eats in the area. It's a Middle Eastern market with a grill in the back. Order your food at the cash register and they call it over the PA, then you pick it up from a window in the back. They have tables set up outside. I love their kubedeh, be sure to order the grilled tomato with it. Friends have said the rose ice cream is good too, but I haven't tried that yet. It's just a few dollars for a plate of freshly cooked, delicious food.
Rose International Market
1060 Castro St, Mountain View, CA 94040