Shell
The US dollar is universal in Vietnam. The Vietnamese locals all collect US dollars. If they don't have the US dollar to find you, they will find your local Vietnamese Dong to see if you want it. I don't see anything in the airport duty-free shop. However, there are some cosmetics and the like. It is quite cheap. The perfume is not bad. There is a discount package at the airport in Hanoi. It is either European chocolate, and Dunhill seems to have seen it. There are also cigarettes.