10,000d for cơm hến (rice soup with clams) on a street filled with cơm hến restaurants. This one had good reviews and it was tasty.
I revisited in August 2017 and without asking, the owner gave me a double portion which was too big and double the price. Either she thought I looked hungry or she saw the chance to make some extra money from a foreigner.
The cơm hến had more herbs and peanuts than the others I've tried and there was a nice taste of garlic in the broth.