Vietnam is a perfect place to spend a month. There are so many activities to do. The best is to start journey either from Ho Chi Minh or Hanoi & cover the distance. The landscapes are amazing. I went to Vietnam for a couple of months back & did it on budget. I spent approx 500 dollar which includes everything visa cost, flight tickets & 12 days cost. I am writing a travel. I would appreciate if you can check it.