Have tried the little taco stand called El Awari on Folsom at 51st St. a few times in the last couple weeks. It's only open from about 10:00 a.m. to 2:00 p.m. everyday but Sunday. A tiny little place, there are one or two plastic tables set up outside. Noontime traffic in and out of the area is pretty intense, and will probably get worse as soon as Trader Joe's opens next door.
Tacos are $1.00 ($1.25 if you want 2 tortillas) and come filled with chicken, carnitas, cabeza or lengua. The chicken and carnita tacos I've tried are pretty good, a bit on the salty side, but generously filled with meat. They add onion and cilantro if you want them. Fresh red and green salsas also available. The generously filled pork tamale ($1.50) was slightly dry on the outside, but still pretty tasty. They also offer burritos for $4.00 along with a nice selection of soft drinks. In summary, a great spot for a quick and cheap lunch in East Sac.