Vietnam can be a confusing and overwhelming place if you just arrived. If you plan a trip to Vietnam, and it is your fist time in Vietnam, you might want to make sure you have a place to sleep. To find cheap hotels and guest houses is not really a problem in Vietnam. But booking in advance can be. Many of the smaller place do not have their own website. This list of budget hotels and guest houses in Vietnam might be helpful. Even if you plan to look for accommodation once you are in-country, sometimes it is a good idea to book at least your first nights accommodation ahead and arrive knowing you have a place to go to.
All hotels and guest houses can be booked online.