A couple of times a week, I like to buy a coca cola from the street vendor near AIS. She and her family are very nice and their prices quite good. I have to pay 5,000 VND ($0.29 US) for a coke and 6,000 ($0.35) )for a cafe sua da.
Street vendors are the most affordable way of buying your drinks and food outside of a restaurant. After awhile, you get to know which are the good vendors and which are the bad.
Oddly enough, I never get sick when I eat food from my favorite street vendors, I only get sick from restaurants nowadays. A friend mentioned that restaurants tend to buy food in bulk or keep leftovers overnight. Street vendors sell all of their food and then close shop. That night or early the next morning, they make a fresh batch of food.
(Waiting for my Coca Cola)