To counter what electrojet said, on a couple of points.
Vietnam is nowhere near as expensive as Hong Kong or Singapore. An "expat" apartment can be had (1-2 bedroom) for 550-1300 dollars. A 3 bedroom house very close to work, in a nice neighborhood goes for about 800. Singapore and Hong Kong the same apartment would be 2500-3500 USD.
Food? If your maid cooks for you every day you can eat like a king for 200 a month per person. If you eat out at "expat" places, like I did, it costs about half what you would pay in a US city, and a quarter of what you would pay in London, Paris, or Singapore. Hong Kong food prices are similar to the US. Singapore are higher than London or Paris.
Expat schools are expensive, I think over 1000 per month per kid. I think the same just about everywhere in Asia.
Overall a fairly cheap place to live. Housing has gone up, but is now coming down.
Really want to live on the cheap? A local girlfriend can get you a real deal on an apartment or house, and local prices on everything.
Locals? The fairer sex is very friendly. The others not. I spent 6 months going to mostly Vietnamese places. I finally got tired of being treated poorly. Not to worry, there are lots of expat restaurants and bar with awesome food and service. I think expat asians get treated better than westerners overall.
Vietnam Airlines treatment? Show up on time, do your job without causing problems and you get treated very well. Far better than most US airlines, including the one I used to work for. I would definitely consider going back to VAC if my next gig doesn't pan out.