We flew Pacific Airlines, HAN to SGN in mid March, one way, for about $100.00 each. No complaints about the flight, which is only a little over an hour. I am sure they served food, but am too tired now to remember much about it.
The Rex hotel, in SGN, can usually be gotten for about $60.00, on the internet, and it is a delightful hotel. PM me if you want more details about SGN or Hanoi.
Kate
PS in the north, don't even bother asking for chicken in a big restaurant.