Mercado de la Sierra
Stunningly good, terrifyingly good... 1445 Shaw Ave, Suite 118, in Clovis CA. A dollar will buy you a snack-size taco, filled with carnitas, carne azada, or chile colorado that's like the Platonic ideal for pot roast, bathed in a moderately spicy red sauce, or in a green sauce that's wonderfully incendiary. You can get huge burritos at $4 apiece, but the rice and beans add nothing; it's better just to buy several tacos.
There's a good selection of sodas, both US and Mexican brands in the refrigerator, fresh tamarindo available at the hot food counter, and a few kinds of Mexican sweets by the check-out.