Banh my in Vietnamese means Bread in English (to write it in Vietnamese: Bánh mỳ)
The traditional style of "banh my" in Viet Nam include: a small loaf of bread, butter, roast pork, Jambon/ham, some vegetable and must have pâté (not pâté de foie gras).
In Hanoi city, the price for a loaf of bread like that varies from $0.5 - $1.5
The Donner Kebeb bread is adopted into Viet Nam for several years, it's Turkish style. I think they are too much onion.