Disclaimer: I love the dish bún chả Hà Nội, it is most definitely my favorite Vietnamese dish.
Bún Chả Hà Nội is a very basic street vendor/simple restaurant which unsurprisingly servers mainly the dish with the same nam. They charge 55,000₫ for the bún chả which includes rice noodles, herbs and leaves, a bowl of grilled meat balls and fatty pork with papaya slices, a glass of ice tea and a cold wet napkin.
I find the bún chả here to be the best one I have tried in Ho Chi Minh City, and I have tried quite a few. I like the limited menu and quality of food here. You get plenty of fresh chili, herbs, pickled garlic etc. so that you can flavor it according to your personal taste.
They also offer crab spring rolls, and bún thịt nướng which is only available in the evenings. The service is quite underwhelming like a true Hanoian establishment, but I would highly recommend it as a stop for lunch or dinner for pretty much anyone who can handle sitting on a plastic stool while eating.