By comparison with other large South East Asia countries, people in Vietnam are overall relatively poor. In 2017 the average monthly wage in Thailand is estimated to be around $438 USD (13,877 THB) whilst in Vietnam it was approximately half that at $236 USD (5,364,000 VND). If you live like a local in Vietnam you can live very cheaply, however, few foreign visitors to Vietnam would live like a local or indeed be able to buy things as cheaply as a local.
Adding up the cost of living in VietnamIf you are planning to rent a flat in a major city or a small house outside a city and live moderately well, but not in luxury, you can expect to your monthly expenses to be in a range from $600 (13,605,442 VND) to $1,200 a month (27,210,884 VND).