there’s lots of good places for vietnamese sandwiches in the $3 range – the famous one is saigon sandwich, at larkin and eddy. if you’re looking for vegetarian options try the one just down the street (on larkin between turk & golden gate), it used to be called ‘wrap express’ but now i think it’s actually called ‘vietnamese sandwich’ at least that’s what it says on the sign.
also – if you get a chance you should really check out dottie’s true blue cafe for breakfast. it’s on jones between ofarrell and geary, only open until 3 pm, and expect to stand in line for a while, but it’s worth it. such good food. i wouldn’t call it cheap but it’s not expensive either. i hear liza minelli eats there.