Local bus is the cheapest transportation means in Vietnam for short-distance destinations. You should get a bus map on internet to know which bus to take and which bus-stop to get on and get off. Pay attention closely to the number of the bus. Do realize that a bus route is two-way and you can easily be confused which bus stop is for which way. For an example, on a two-way street, there are bus stops for the same bus on both sides. If you get on the wrong bus, get off immediately. Most of the drivers and driver assistants don’t speak English, preparing beforehand is a must. Timbus is a decent application to find bus route in Hanoi and Tramoc offers information of Hanoi bus network in English.
And also Bus map for Ho Chi Minh city is also available.
In Hanoi, local buses are operated by Hanoibus, go to their website http://transerco.vn/Default.aspx?pageid=253 to have the schedule (only in Vietnamese but understandable). Price for city bus is 7,000VND per person, from city to suburb areas, depends.
In Ho Chi Minh city, buses are managed by Department of Transportation http://www.buyttphcm.com.vn/Default.aspx (Vietnamese only). On this website you can find a map of bus-stops for each route (trạm dừng nhà chờ) and ticket prices (vé xe buýt). The price is from 5000VND – less than 18km, 6000VND – more than 18km, 7000VND – 10,000VND for fast buses (13, 94) and night bus (96). Ticket books (30 tickets /book) are priced from 112,000VND – 135,000VND according to the distance.
In provinces and smaller cities, local buses are lesser than in big cities, mostly buses run by private companies to tourist destinations with higher prices. One thing you won’t like about local buses is that the quality of service probably doesn’t meet your expectations. Besides being crowed most of the time, not fully equipped, the security isn’t ensured and you might be stolen without knowing.